diff --git a/code/Controllers/CMSPageHistoryController.php b/code/Controllers/CMSPageHistoryController.php
index 923c192c..eba00f31 100644
--- a/code/Controllers/CMSPageHistoryController.php
+++ b/code/Controllers/CMSPageHistoryController.php
@@ -396,11 +396,11 @@ class CMSPageHistoryController extends CMSMain
         $toVersionRecord = Versioned::get_version(SiteTree::class, $id, $toVersion);
 
         if (!$fromVersionRecord) {
-            user_error("Can't find version $fromVersion of page $id", E_USER_ERROR);
+            throw new \Exception("Can't find version $fromVersion of page $id");
         }
 
         if (!$toVersionRecord) {
-            user_error("Can't find version $toVersion of page $id", E_USER_ERROR);
+            throw new \Exception("Can't find version $toVersion of page $id");
         }
 
         if (!$record) {
diff --git a/code/Tasks/RemoveOrphanedPagesTask.php b/code/Tasks/RemoveOrphanedPagesTask.php
index 2c19e02e..c422e747 100644
--- a/code/Tasks/RemoveOrphanedPagesTask.php
+++ b/code/Tasks/RemoveOrphanedPagesTask.php
@@ -96,7 +96,7 @@ in the other stage:<br />
 
         $fields->push(new HeaderField(
             'Header',
-            _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.HEADER', 'Remove all orphaned pages task')
+            _t(__CLASS__ . '.HEADER', 'Remove all orphaned pages task')
         ));
         $fields->push(new LiteralField(
             'Description',
@@ -134,14 +134,14 @@ in the other stage:<br />
                 'SelectAllLiteral',
                 sprintf(
                     '<p><a href="#" onclick="javascript:jQuery(\'#Form_Form_OrphanIDs :checkbox\').attr(\'checked\', \'checked\'); return false;">%s</a>&nbsp;',
-                    _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.SELECTALL', 'select all')
+                    _t(__CLASS__ . '.SELECTALL', 'select all')
                 )
             ));
             $fields->push(new LiteralField(
                 'UnselectAllLiteral',
                 sprintf(
                     '<a href="#" onclick="javascript:jQuery(\'#Form_Form_OrphanIDs :checkbox\').attr(\'checked\', \'\'); return false;">%s</a></p>',
-                    _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.UNSELECTALL', 'unselect all')
+                    _t(__CLASS__ . '.UNSELECTALL', 'unselect all')
                 )
             ));
             $fields->push(new OptionsetField(
@@ -149,13 +149,13 @@ in the other stage:<br />
                 _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.CHOOSEOPERATION', 'Choose operation:'),
                 [
                     'rebase' => _t(
-                        'SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.OPERATION_REBASE',
+                        __CLASS__ . '.OPERATION_REBASE',
                         sprintf(
                             'Rebase selected to a new holder page "%s" and unpublish. None of these pages will show up for website visitors.',
                             $this->rebaseHolderTitle()
                         )
                     ),
-                    'remove' => _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.OPERATION_REMOVE', 'Remove selected from all stages (WARNING: Will destroy all selected pages from both stage and live)'),
+                    'remove' => _t(__CLASS__ . '.OPERATION_REMOVE', 'Remove selected from all stages (WARNING: Will destroy all selected pages from both stage and live)'),
                 ],
                 'rebase'
             ));
@@ -164,7 +164,7 @@ in the other stage:<br />
                 sprintf(
                     '<p class="message">%s</p>',
                     _t(
-                        'SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.DELETEWARNING',
+                        __CLASS__ . '.DELETEWARNING',
                         'Warning: These operations are not reversible. Please handle with care.'
                     )
                 )
@@ -174,7 +174,7 @@ in the other stage:<br />
                 'NotFoundLabel',
                 sprintf(
                     '<p class="message">%s</p>',
-                    _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.NONEFOUND', 'No orphans found')
+                    _t(__CLASS__ . '.NONEFOUND', 'No orphans found')
                 )
             ));
         }
@@ -184,7 +184,7 @@ in the other stage:<br />
             'SilverStripe\\Forms\\Form',
             $fields,
             new FieldList(
-                new FormAction('doSubmit', _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.BUTTONRUN', 'Run'))
+                new FormAction('doSubmit', _t(__CLASS__ . '.BUTTONRUN', 'Run'))
             )
         );
 
@@ -217,7 +217,7 @@ in the other stage:<br />
                 $successIDs = $this->rebaseOrphans($data['OrphanIDs']);
                 break;
             default:
-                user_error(sprintf("Unknown operation: '%s'", $data['OrphanOperation']), E_USER_ERROR);
+                throw new \InvalidArgumentException(sprintf("Unknown operation: '%s'", $data['OrphanOperation']));
         }
 
         $content = '';
@@ -228,7 +228,7 @@ in the other stage:<br />
             }
             $content .= "</ul>";
         } else {
-            $content = _t('SilverStripe\\CMS\\Tasks\\RemoveOrphanedPagesTask.NONEREMOVED', 'None removed');
+            $content = _t(__CLASS__ . '.NONEREMOVED', 'None removed');
         }
 
         return $this->customise([