Toilet Seat Recomendations Please!

We have been off and on toilet training for a few weeks now and with the help of reward charts are doing fairly well, asking to go occasionally and havng dry nappy in between us taking him to the toilet, even managing a couple of hours in normal pants without too many major accidents. However we are struggling with a toilet seat! at the moment he has a potty downstairs which he happily uses but more often is wanting to sit on the big toilet. We have a Thomas Trainer seat from Mothercare which he hates as it's hard, moves about and not big enough for his bum to get on and get his winky in a comfy place! Upstairs we've got a cheap padded one from Ethel Austin which he likes but isn't big enough to sit safely inside the normal toilet seat and we've had a few sprinkle accidents as there is no guard on the front!

So, my question is - can anyone receommend a comfy seat, that fits a toilet well and is designed to stop spray whilst not squashing a winky?! ?

Having spent quite a bit on mistakes in the past i'm trying to save pennies by not making more costly mistakes! ;\)

Thanks