Issues with a simple app

I'm working on a really simple app - here is the code:

<TableView>
      <TableView.Root>
        <TableSection Title="About You">
          <ViewCell>
            <Grid>
              <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition Width="*"/>
              </Grid.ColumnDefinitions>
              <Label Text="Name" Font="Large" YAlign="Center" WidthRequest="100"></Label>
              <Entry Grid.Column="1" HorizontalOptions="FillAndExpand"/>
            </Grid>
          </ViewCell>
        </TableSection>
      </TableView.Root>
    </TableView>

On Android this renders exactly like I would expect, but it's impossible to type anything into the TextView that gets rendered
On Windows phone the textbox is tiny (1 pixel)

I've also noticed the following other issues:
Windows Phone: Changing the text on a button once it's been rendered doesn't re-size the buttons border correctly (or align the text correctly)- set it to something small, then something big.
Windows Phone: Having the following code as page 1:

<StackLayout>
    <Label Text="A big test string " VerticalOptions="Center" HorizontalOptions="Center" />
  <Button x:Name="New">Go!</Button>
  </StackLayout>

navigating to any second page then back again causes a strange layout were the text appears in the label to have been bound to a width of 50

I know I could use the EntryCell, but I want to have a fixed width on the label, so I've had to implement it as above.

Thanks

Ross