Iain,

Thanks for this.

The assumptions on it being 607 sqaudron were from two points:-

The codes being AF:U
The photo came from Canada near where W H Whitty lived after return to Canada.

I must admit that I had not thought about the posibility that it could be the AFDU. I am aware that they also used AF as some of the IWM photos are incorrectly captioned as 607 squadron (They were MkII spitfires if I remember correctly from when I visited the IWM).

Perhaps we need to further look at the location to see if this ties in with Northolt.

Unfortunately the source in Canada has no information on the photograph.