Thanks for the replies.
I guess I should be grateful that he eats so well! I seem to have turned him the opposite way now!
Yesterday I decided to give him 6oz bottles at lunch and tea instead of 5oz, and i gave these before solids instead of after. Then he only ate a fraction of what he normally would at his solid meals. And the same today after having a 7oz bottle at lunch. But I guess this is good because it means he's still getting his main nutrition from the milk and he can stop when full up after all, he won't just keep going til he pops which I had started to think!! The result of the last two days has been that he has definitely been sick a lot less than before which is good.....