WIll only sit on the toilet at nursery

[shish]

My ds is 2 and a half years old. They have been putting him on the toilet at the nursery at nappy changing time for a while now and they're telling me that he has no problems and he is quite happy to do this. However, at home it is a completely different story. He refuses point blank to sit on the toilet and insists on nappies. Don't know what to do!! We have bought him a really nice 'Thomas' seat as he is mad into this at the moment but he just wants to play with it.

Any advice would be gratefully recieved.

Do you have a step? Is it possible that the toilet at nursery is a mini-low one? Or is it possible he's having a laugh at your expense and has learned that it gets a rise out of mum to refuse to sit?

Strategies:

(1) Borrow another toddler who is willing to sit on the loo and let him come over to play and use the loo while your DS is around - praise the friend - a lot. I'm betting he does it at nursery when his mates do it!
(2) Say 'ah never mind you are probably too young' and don't mention it for a month, then start again.

I get the feeling he's either having a laugh at my expense or he just doesn't feel ready to give up on his nappies..

Does anyone else have any advice???