Thanks Deb - funny you mention eggs as he used to eat them until he was sick once (only time had a tummy bug) and wouldn't touch them after that. We tried again the other day and he ate them but the next day he had funny spots on his face which we were wondering was related ...
In terms of the other food it just leaves a red, sore mark wherever the poo has touched his skin which clears up within a day or 2 with or without cream (he wears washable nappies but non-chemically disposable at night).
Will make a note in his red book about the gluten intolerence theory to remind me to mention it to dietician ....