609 Squadron Spitfire in pencil

Here's a WIP of a scene depicting the Spitfire Mk Ia flown by Pilot Officer JC Dundas of No 609 Sqn, 1940. He and his wingman have just spotted bogeys and are peeling off to the attack. I will place a squadron of He-111's in the distance just above the horizon line to finish off the piece. I'm not sure about the bottom right side of this piece as I don't want it to get too heavy so I may need to break up the cloud somewhat in this part of the composition. I would like to do this one in acrylics later on.