Hi Paul,
I would suggest you to put footer TextBlock right below the ListView.
Currently ListView Footer template will scrolling with the content, we do not have any other solution for you to keep footer on screen, we can only make thing looks like a fixed footer as you need.

<StackPanel>
<ListView>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
<x:String>asdsadasd</x:String>
</ListView>
<TextBlock x:Name="footer" Foreground="White" Text="This is footer"></TextBlock>
</StackPanel>
--James
<THE CONTENT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS OR IMPLIED>
Thanks
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