diff --git a/src/Forms/PrintableTransformation_TabSet.php b/src/Forms/PrintableTransformation_TabSet.php
index f25598e5a..2be4f72d7 100644
--- a/src/Forms/PrintableTransformation_TabSet.php
+++ b/src/Forms/PrintableTransformation_TabSet.php
@@ -19,9 +19,9 @@ class PrintableTransformation_TabSet extends TabSet
     public function FieldHolder($properties = array())
     {
         // This gives us support for sub-tabs.
-        $tag = ($this->tabSet) ? "h2>" : "h1>";
+        $tag = $this->getTabSet() ? 'h2>' : 'h1>';
         $retVal = '';
-        foreach ($this->children as $tab) {
+        foreach ($this->getChildren() as $tab) {
             $retVal .= "<$tag" . $tab->Title() . "</$tag\n";
             $retVal .= $tab->FieldHolder();
         }
diff --git a/src/Forms/TabSet.php b/src/Forms/TabSet.php
index da18e9d48..dc0b60217 100644
--- a/src/Forms/TabSet.php
+++ b/src/Forms/TabSet.php
@@ -106,9 +106,8 @@ class TabSet extends CompositeField
     {
         if ($this->tabSet) {
             return $this->tabSet->ID() . '_' . $this->id . '_set';
-        } else {
-            return $this->id;
         }
+        return $this->id;
     }
 
     /**
diff --git a/tests/php/Forms/DisabledTransformationTest.php b/tests/php/Forms/DisabledTransformationTest.php
new file mode 100644
index 000000000..74b460f39
--- /dev/null
+++ b/tests/php/Forms/DisabledTransformationTest.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace SilverStripe\Forms\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Forms\DisabledTransformation;
+use SilverStripe\Forms\TextField;
+
+class DisabledTransformationTest extends SapphireTest
+{
+    public function testTransform()
+    {
+        $field = new TextField('Test');
+
+        $transformation = new DisabledTransformation();
+        $newField = $transformation->transform($field);
+
+        $this->assertTrue($newField->isDisabled(), 'Transformation failed to transform field to be disabled');
+    }
+}
diff --git a/tests/php/Forms/PrintableTransformationTest.php b/tests/php/Forms/PrintableTransformationTest.php
new file mode 100644
index 000000000..8a54d8d49
--- /dev/null
+++ b/tests/php/Forms/PrintableTransformationTest.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace SilverStripe\Forms\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Forms\PrintableTransformation;
+use SilverStripe\Forms\PrintableTransformation_TabSet;
+use SilverStripe\Forms\Tab;
+use SilverStripe\Forms\TabSet;
+
+class PrintableTransformationTest extends SapphireTest
+{
+    public function testTransformTabSet()
+    {
+        $tab1 = new Tab('Main');
+        $tab2 = new Tab('Settings');
+        $tabSet = new TabSet('Root', 'Root', $tab1, $tab2);
+
+        $transformation = new PrintableTransformation();
+        $result = $transformation->transformTabSet($tabSet);
+
+        $this->assertInstanceOf(PrintableTransformation_TabSet::class, $result);
+        $this->assertSame('Root', $result->Title());
+    }
+}
diff --git a/tests/php/Forms/PrintableTransformation_TabSetTest.php b/tests/php/Forms/PrintableTransformation_TabSetTest.php
new file mode 100644
index 000000000..11ca4efd8
--- /dev/null
+++ b/tests/php/Forms/PrintableTransformation_TabSetTest.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace SilverStripe\Forms\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Forms\PrintableTransformation_TabSet;
+use SilverStripe\Forms\Tab;
+use SilverStripe\Forms\TabSet;
+
+class PrintableTransformation_TabSetTest extends SapphireTest
+{
+    public function testFieldHolder()
+    {
+        $tabs = [
+            new Tab('Main'),
+            new Tab('Secondary'),
+            $optionsTabSet = new TabSet(
+                'Options',
+                'Options',
+                new Tab('Colours'),
+                new Tab('Options')
+            ),
+        ];
+
+        $transformationTabSet = new PrintableTransformation_TabSet($tabs);
+        $result = $transformationTabSet->FieldHolder();
+
+        $this->assertContains('<h1>Main</h1>', $result);
+        $this->assertContains('<h1>Secondary</h1>', $result);
+
+        $transformationTabSet->setTabSet($optionsTabSet);
+        $result = $transformationTabSet->FieldHolder();
+
+        $this->assertContains('<h2>Options</h2>', $result);
+    }
+}