BoxView appearing on iOS but not on Android

I've got the following XAML layout:

        <StackLayout Orientation="Vertical">
            <Label x:Name="lblAppointmentcount"
            Font="15"
            XAlign = "Center"
            Text="{Binding AppointmentCount,StringFormat = '{0} Appointments found'}"/>
            <ListView x:Name="lstAppointments">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <StackLayout Orientation = "Horizontal">
                                    <BoxView x:Name="boxStatus" BackgroundColor = "Blue" WidthRequest = "15" HeightRequest = "40"/>
                                <StackLayout Orientation = "Vertical">
                                    <StackLayout Orientation="Horizontal">
                                        <Label
                                        Font = "15" 
                                        Text="{Binding QuoteNo, StringFormat='Q{0}'}" YAlign="Center" />
                                    </StackLayout>
                                    <StackLayout Orientation= "Horizontal">
                                        <Label x:Name = "ClientAddress" Text = "{Binding ClientNameAndAddress}" />
                                    </StackLayout>
                                </StackLayout>
                            </StackLayout>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </StackLayout>

This shows up fine on iOS, with a blue box to the left of my list items. However, on Android, the box is not having its colour set. I can see the space being allocated for the BoxView, but it's black.

What am I missing?