RAF Waddington Wartime aircraft part ID

Hi All,

This small piece of aircraft was found recently on the airfield at RAF Waddington. It would be nice if anyone can positively identify it please. My hunch is that it’s part of an FN5 cupola due to the curved edge and sandwiched Perspex. Failing that, maybe Hampden related?

Thanks[ATTACH=CONFIG]238545[/ATTACH][ATTACH=CONFIG]238546[/ATTACH]