There is an online MCN store that sells bands that you put around the top of the nappy (like a little belly band when you're pregnant) so the little munchkins can't undo the nappies...
Can't for the life of me think of the store...
Will be back if I can find it in my favourites....
ETA: Woolies is a great idea Donna!
I'll have to use that excuse to buy more when Pickle starts going through this stage! LOL!