See if you can get hold of a silver grey belaclava. Get a white sheet and cut a round hole in the middle of it, to fit it over his head. Draw a red cross on the front of the sheet with magic marker. When he puts the sheet on, put a belt around the waist, put the belaclava on, give him a plastic sword and he's sir Lancelot. The wife calls me Peter Pan. Good Luck. I'm a big kid at heart.
I,m sure there's a party dressing up show in Newcastle.Look it up on the net.