Setting Title on Xaml ContentPage not working

I've created a very simple Xaml ContentPage and got an MVVM scenario working all fine, but when I set the Title on the Main ContentPage element it isn't showing any title at all, its just shows the ContentPage content - am I missing something?

Content Page:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
                   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                   x:Class="MyApp.View.HomeView"
        xmlns:viewModel="clr-namespace:MyApp.ViewModel;assembly=MyApp"
        Title="Testing">

    <ContentPage.BindingContext>
        <viewModel:HomeViewModel />
    </ContentPage.BindingContext>

    <Label Text="{Binding Message}" 
            VerticalOptions="Center" 
            HorizontalOptions="Center">
    </Label>

</ContentPage>

I'm debugging on Android using both Genymotion and a device (Galaxy S4 + Nexus 5) and I'm just ot seeing any action bar at all.

Thanks

Matt