Thanks all great advice in here for me to try out. Amazingly for the last couple nights he has stayed in his bed (since I made this post!)
But no doubt he'll start it up again so ill know what to try out. I am probably being too soft with him with the middle of the night wakings.
As for the holding the door shut when i first put him to bed, he actually doesn't sound stressed out in bed at all... like sure he'll protest cry at first as for weeks now he has been coming out as he pleases, but once he gives up and puts himself back to bed he lays in there talking to his monkey teddy. I check on him regularly too, and last night when i opened the door after i heard he put himself to bed - he just smiled at me, I said 'goodnight darling' and closed the door and he had accepted it by then. Far from stressed! All kids are different.