Dont think its a Valiant, I think its smaller cos if you look closely, you'll see a roof in the background and the Valiant is actually quite a big big of real-estate !
It looks like a De-Havilland of some sort for some reason...was thinking Mosquito but its not one of them...and it reminds me of the Doves at White Waltham when I was a lad !.
Don't know of any Doves flying and the ones in museums look a bit different, so I'll have a go at a Heron ?