diff --git a/_config.php b/_config.php
index 9e519d4a..71c7914c 100644
--- a/_config.php
+++ b/_config.php
@@ -5,5 +5,4 @@
 
 // Avoid creating global variables
 call_user_func(function () {
-
 });
diff --git a/lang/_manifest_exclude b/lang/_manifest_exclude
new file mode 100644
index 00000000..e69de29b
diff --git a/lang/en.yml b/lang/en.yml
new file mode 100644
index 00000000..b4c16635
--- /dev/null
+++ b/lang/en.yml
@@ -0,0 +1,5 @@
+en:
+  SilverStripe\LinkField\Form\PhoneField:
+    INVALID: 'Please enter a valid phone number'
+  SilverStripe\LinkField\Validators\HasOneCanViewValidator:
+    CANNOTBEVIEWED: '{name} cannot be viewed'
diff --git a/src/Form/LinkFieldTreeDropdownField.php b/src/Form/LinkFieldTreeDropdownField.php
new file mode 100644
index 00000000..881edb57
--- /dev/null
+++ b/src/Form/LinkFieldTreeDropdownField.php
@@ -0,0 +1,27 @@
+<?php
+
+namespace SilverStripe\LinkField\Form;
+
+use SilverStripe\Forms\TreeDropdownField;
+
+/**
+ * This class exists as workaround to an issue where RequiredFields is not respected
+ * when selecting an empty value using TreeDropdownField because RequiredFields views
+ * a value of 0 (ie no relation selected) as as non-emtpy value, as RequiredFields only counts
+ * an emtpy string as a missing value
+ *
+ * This class in only intended to be used in SiteTreeLink which also has a RequiredFields of ['PageID']
+ */
+class LinkFieldTreeDropdownField extends TreeDropdownField
+{
+    /**
+     * This is passed to the frontent via FormField::getSchemaValidation()
+     * and used in Validator.js
+     */
+    public function getSchemaValidation()
+    {
+        $rules = parent::getSchemaValidation();
+        $rules['regex'] = ['pattern' => '[^0]'];
+        return $rules;
+    }
+}
diff --git a/src/Form/PhoneField.php b/src/Form/PhoneField.php
new file mode 100644
index 00000000..089e09df
--- /dev/null
+++ b/src/Form/PhoneField.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace SilverStripe\LinkField\Form;
+
+use SilverStripe\Forms\TextField;
+use SilverStripe\Forms\Validator;
+
+/**
+ * Text input field with validation for a phone number
+ */
+class PhoneField extends TextField
+{
+    /**
+     * This needs to be not surronded by regex delimiters so that it works on the frontend
+     */
+    private const RX = '^[()\- 0-9]+$';
+
+    /**
+     * This is used for the <input> element type="tel" attribute
+     * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/tel
+     */
+    protected $inputType = 'tel';
+
+    /**
+     * This is added as a classname to the <input> element
+     */
+    public function Type()
+    {
+        return 'phone text';
+    }
+
+    /**
+     * @param Validator $validator
+     *
+     * @return string
+     */
+    public function validate($validator)
+    {
+        $result = true;
+        $this->value = trim($this->value ?? '');
+        if ($this->value && !preg_match('#' . self::RX . '#', $this->value)) {
+            $validator->validationError(
+                $this->name,
+                _t(__CLASS__ . '.INVALID', 'Please enter a valid phone number'),
+                'validation'
+            );
+            $result = false;
+        }
+        return $this->extendValidationResult($result, $validator);
+    }
+
+    /**
+     * This is passed to the frontent via FormField::getSchemaValidation()
+     * and used in Validator.js
+     */
+    public function getSchemaValidation()
+    {
+        $rules = parent::getSchemaValidation();
+        $rules['regex'] = ['pattern' => self::RX];
+        return $rules;
+    }
+}
diff --git a/src/Models/EmailLink.php b/src/Models/EmailLink.php
index 410455db..ea3d1410 100644
--- a/src/Models/EmailLink.php
+++ b/src/Models/EmailLink.php
@@ -4,6 +4,8 @@
 
 use SilverStripe\Forms\EmailField;
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
 
 /**
  * A link to an Email address.
@@ -28,7 +30,6 @@ public function getCMSFields(): FieldList
         $this->beforeUpdateCMSFields(static function (FieldList $fields) {
             $fields->replaceField('Email', EmailField::create('Email'));
         });
-
         return parent::getCMSFields();
     }
 
@@ -36,4 +37,11 @@ public function getURL(): string
     {
         return $this->Email ? sprintf('mailto:%s', $this->Email) : '';
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['Email']));
+        return $validator;
+    }
 }
diff --git a/src/Models/ExternalLink.php b/src/Models/ExternalLink.php
index c51fb50c..b47d2fcc 100644
--- a/src/Models/ExternalLink.php
+++ b/src/Models/ExternalLink.php
@@ -2,6 +2,9 @@
 
 namespace SilverStripe\LinkField\Models;
 
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
+
 /**
  * A link to an external URL.
  *
@@ -24,4 +27,11 @@ public function getURL(): string
     {
         return $this->ExternalUrl ?? '';
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['ExternalUrl']));
+        return $validator;
+    }
 }
diff --git a/src/Models/FileLink.php b/src/Models/FileLink.php
index 0d40b933..0dbbe34b 100644
--- a/src/Models/FileLink.php
+++ b/src/Models/FileLink.php
@@ -3,6 +3,8 @@
 namespace SilverStripe\LinkField\Models;
 
 use SilverStripe\Assets\File;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
 
 /**
  * A link to a File track in asset-admin
@@ -42,4 +44,11 @@ public function getURL(): string
 
         return $file->exists() ? (string) $file->getURL() : '';
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['File']));
+        return $validator;
+    }
 }
diff --git a/src/Models/Link.php b/src/Models/Link.php
index 87d2de0f..5b3671ac 100644
--- a/src/Models/Link.php
+++ b/src/Models/Link.php
@@ -16,6 +16,9 @@
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\View\Requirements;
+use SilverStripe\Forms\Form;
+use SilverStripe\ORM\ValidationResult;
+use SilverStripe\Forms\TreeDropdownField;
 
 /**
  * A Link Data Object. This class should be a subclass, and you should never directly interact with a plain Link
@@ -110,6 +113,36 @@ public function getCMSCompositeValidator(): CompositeValidator
         return $validator;
     }
 
+    /**
+     * This method is used to validate the dataobject before saving as part of DataObject::write()
+     * Linkfield works a bit differently from normal forms, because where the modal data is turned
+     * into JSON and saved into a single JsonField and in saveInto() the JSON is loaded into the
+     * dataobject using DataObject::setData($data)
+     * Because of this alternate method of saving, the getCMSCompositeValidator() isn't called
+     * so we need to call it manually here by loading it into a temporary Form
+     *
+     * @return ValidationResult
+     */
+    public function validate()
+    {
+        $parentResult = parent::validate();
+        $validator = $this->getCMSCompositeValidator();
+        $form = Form::create(null, Form::DEFAULT_NAME, $this->getCMSFields());
+        $form->setValidator($validator);
+        $form->loadDataFrom($this);
+        // Workaround an issue where RequiredFields does not treat RelationID's of 0 as missing
+        // by changing the value of any TreeDropdowns on the field with a value of 0 to empty string
+        /** @var FormField $field */
+        foreach ($form->Fields()->flattenFields() as $field) {
+            if (is_a($field, TreeDropdownField::class) && $field->Value() === 0) {
+                $field->setValue('');
+            }
+        }
+        $formResult = $form->validationResult();
+        $combinedResult = $parentResult->combineAnd($formResult);
+        return $combinedResult;
+    }
+
     /**
      * Form hook defined in @see Form::saveInto()
      * We use this to work with an in-memory only field
diff --git a/src/Models/PhoneLink.php b/src/Models/PhoneLink.php
index 855e3b1c..c0d20dd4 100644
--- a/src/Models/PhoneLink.php
+++ b/src/Models/PhoneLink.php
@@ -2,6 +2,11 @@
 
 namespace SilverStripe\LinkField\Models;
 
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
+use SilverStripe\Forms\FieldList;
+use SilverStripe\LinkField\Form\PhoneField;
+
 /**
  * A link to a phone number
  *
@@ -15,6 +20,14 @@ class PhoneLink extends Link
         'Phone' => 'Varchar(255)',
     ];
 
+    public function getCMSFields(): FieldList
+    {
+        $this->beforeUpdateCMSFields(function (FieldList $fields) {
+            $fields->replaceField('Phone', PhoneField::create('Phone'));
+        });
+        return parent::getCMSFields();
+    }
+
     public function generateLinkDescription(array $data): string
     {
         return isset($data['Phone']) ? $data['Phone'] : '';
@@ -24,4 +37,11 @@ public function getURL(): string
     {
         return $this->Phone ? sprintf('tel:%s', $this->Phone) : '';
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['Phone']));
+        return $validator;
+    }
 }
diff --git a/src/Models/SiteTreeLink.php b/src/Models/SiteTreeLink.php
index f3f611d8..c8b02572 100644
--- a/src/Models/SiteTreeLink.php
+++ b/src/Models/SiteTreeLink.php
@@ -7,7 +7,10 @@
 use SilverStripe\Control\Controller;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\TextField;
-use SilverStripe\Forms\TreeDropdownField;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
+use SilverStripe\LinkField\Form\LinkFieldTreeDropdownField;
+use SilverStripe\LinkField\Validators\HasOneCanViewValidator;
 
 /**
  * A link to a Page in the CMS
@@ -63,7 +66,7 @@ public function getCMSFields(): FieldList
 
             $fields->insertAfter(
                 'Title',
-                TreeDropdownField::create(
+                LinkFieldTreeDropdownField::create(
                     'PageID',
                     'Page',
                     SiteTree::class,
@@ -128,4 +131,12 @@ public function getTitle(): ?string
         // Use page title as a default value in case CMS user didn't provide the title
         return $page->Title;
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['PageID']));
+        $validator->addValidator(HasOneCanViewValidator::create(['PageID']));
+        return $validator;
+    }
 }
diff --git a/src/Validators/HasOneCanViewValidator.php b/src/Validators/HasOneCanViewValidator.php
new file mode 100644
index 00000000..d6fe6857
--- /dev/null
+++ b/src/Validators/HasOneCanViewValidator.php
@@ -0,0 +1,98 @@
+<?php
+
+namespace SilverStripe\LinkField\Validators;
+
+use SilverStripe\Core\Config\Config;
+use SilverStripe\Forms\Validator;
+use SilverStripe\Forms\FormField;
+
+/**
+ * Call a canView() check to validate a has_one relation
+ */
+class HasOneCanViewValidator extends Validator
+{
+    /**
+     * List of has_one relation fields (with 'ID' suffixed) that need to pass a canView() check
+     */
+    private array $relationFields;
+
+    /**
+     * Pass each field to be validated as a separate argument to the constructor
+     * of this object. (an array of elements are ok).
+     */
+    public function __construct()
+    {
+        parent::__construct();
+        $relationFields = func_get_args();
+        if (isset($relationFields[0]) && is_array($relationFields[0])) {
+            $relationFields = $relationFields[0];
+        }
+        foreach ($relationFields as $i => $relationField) {
+            if (!preg_match('#ID$#', $relationField)) {
+                $relationFields[$i] .= 'ID';
+            }
+        }
+        $this->relationFields = $relationFields;
+    }
+
+    /**
+     * Allows validation of fields via specification of a php function for
+     * validation which is executed after the form is submitted.
+     *
+     * @param array $data
+     * @return boolean
+     */
+    public function php($data)
+    {
+        $valid = true;
+        $fields = $this->form->Fields();
+        $dataObjectClassName = get_class($this->form->getRecord());
+        $hasOnes = Config::inst()->get($dataObjectClassName, 'has_one');
+
+        foreach ($this->relationFields as $fieldName) {
+            if ($fieldName instanceof FormField) {
+                $formField = $fieldName;
+                $fieldName = $fieldName->getName();
+            } else {
+                $formField = $fields->dataFieldByName($fieldName);
+            }
+
+            if (!$formField) {
+                continue;
+            }
+
+            $value ??= $data[$fieldName];
+            if (!$value) {
+                continue;
+            }
+
+            $relation = preg_replace('#ID$#', '', $fieldName);
+            $relationClassName = $hasOnes[$relation];
+            $relationObject = $relationClassName::get()->byID($value);
+
+            if ($relationObject && $relationObject->canView()) {
+                // It's valid
+                // Note if $relationObject is null then still fail this CanView validator the same
+                // way so that user cannot tell if the relation exists or not
+                continue;
+            }
+
+            $errorMessage = _t(
+                __CLASS__ . '.CANNOTBEVIEWED',
+                '{name} cannot be viewed',
+                [
+                    'name' => strip_tags(
+                        '"' . ($formField->Title() ? $formField->Title() : $fieldName) . '"'
+                    )
+                ]
+            );
+            if ($msg = $formField->getCustomValidationMessage()) {
+                $errorMessage = $msg;
+            }
+            $this->validationError($fieldName, $errorMessage, 'required');
+            $valid = false;
+        }
+
+        return $valid;
+    }
+}