Thanks Jen and Zoey, he's definitely a good large...
I'll look into the zorb sheet, especially seeing as its really thin and can be hidden like you say Zoey.
He's definitely flooding Kirsty, his nappiescan last anything from 3 hours (if i'm extremely lucky) to 1/2 an hour because he's decided to go then. I'm trying not to force the potty issue with him but he was worried when the rat got flushed and keeps checking the loo now...Which is progress, he wouldn't even go near it before. So its not all bad i guess.
I'm not keen on pockets for him though, i've tried in the past and they just didn't fit him right and i've to much wool not to use.