Thanks, it's funny, I though that once the nap was gone, that was it, but obviously not! He is a "touchy" one though and has never coped well with being tired so if he needs it, he needs it.
Today he had an appointment 1.30-2.30 & despite quiet time before and after, he didn't sleep. By 5.30 we had screaming at the top of his lungs and tears, over a piece of fish finger which fell on the floor. Previously I'd put this down to "threenager" behaviour but having had a few days of better behaviour when he napped I realise it's related to tiredness. On plus side he took himself to bed at 6.45! Fingers crossed for a long night.
I think I'll continue to give him quiet time and opportunity to nap mid afternoon and see what he does.