diff --git a/wagtail/tests/demosite/models.py b/wagtail/tests/demosite/models.py
index 724e61600..2f23d1991 100644
--- a/wagtail/tests/demosite/models.py
+++ b/wagtail/tests/demosite/models.py
@@ -162,8 +162,8 @@ class HomePageRelatedLink(Orderable, AbstractRelatedLink):
 HomePage.content_panels = Page.content_panels + [
     FieldPanel('body', classname="full"),
 
-    InlinePanel(HomePage, 'carousel_items', label="Carousel items"),
-    InlinePanel(HomePage, 'related_links', label="Related links"),
+    InlinePanel('carousel_items', label="Carousel items"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 
@@ -202,9 +202,9 @@ class StandardPageRelatedLink(Orderable, AbstractRelatedLink):
 
 StandardPage.content_panels = Page.content_panels + [
     FieldPanel('intro', classname="full"),
-    InlinePanel(StandardPage, 'carousel_items', label="Carousel items"),
+    InlinePanel('carousel_items', label="Carousel items"),
     FieldPanel('body', classname="full"),
-    InlinePanel(StandardPage, 'related_links', label="Related links"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 StandardPage.promote_panels = [
@@ -239,7 +239,7 @@ class StandardIndexPageRelatedLink(Orderable, AbstractRelatedLink):
 
 StandardIndexPage.content_panels = Page.content_panels + [
     FieldPanel('intro', classname="full"),
-    InlinePanel(StandardIndexPage, 'related_links', label="Related links"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 StandardIndexPage.promote_panels = [
@@ -292,8 +292,8 @@ class BlogEntryPageTag(TaggedItemBase):
 BlogEntryPage.content_panels = Page.content_panels + [
     FieldPanel('date'),
     FieldPanel('body', classname="full"),
-    InlinePanel(BlogEntryPage, 'carousel_items', label="Carousel items"),
-    InlinePanel(BlogEntryPage, 'related_links', label="Related links"),
+    InlinePanel('carousel_items', label="Carousel items"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 BlogEntryPage.promote_panels = [
@@ -354,7 +354,7 @@ class BlogIndexPageRelatedLink(Orderable, AbstractRelatedLink):
 
 BlogIndexPage.content_panels = Page.content_panels + [
     FieldPanel('intro', classname="full"),
-    InlinePanel(BlogIndexPage, 'related_links', label="Related links"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 
@@ -455,10 +455,10 @@ EventPage.content_panels = Page.content_panels + [
     FieldPanel('audience'),
     FieldPanel('cost'),
     FieldPanel('signup_link'),
-    InlinePanel(EventPage, 'carousel_items', label="Carousel items"),
+    InlinePanel('carousel_items', label="Carousel items"),
     FieldPanel('body', classname="full"),
-    InlinePanel(EventPage, 'speakers', label="Speakers"),
-    InlinePanel(EventPage, 'related_links', label="Related links"),
+    InlinePanel('speakers', label="Speakers"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 EventPage.promote_panels = [
@@ -498,7 +498,7 @@ class EventIndexPageRelatedLink(Orderable, AbstractRelatedLink):
 
 EventIndexPage.content_panels = Page.content_panels + [
     FieldPanel('intro', classname="full"),
-    InlinePanel(EventIndexPage, 'related_links', label="Related links"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 
@@ -552,7 +552,7 @@ PersonPage.content_panels = Page.content_panels + [
     FieldPanel('biography', classname="full"),
     ImageChooserPanel('image'),
     MultiFieldPanel(ContactFieldsMixin.panels, "Contact"),
-    InlinePanel(PersonPage, 'related_links', label="Related links"),
+    InlinePanel('related_links', label="Related links"),
 ]
 
 PersonPage.promote_panels = [