He's mostly wearing pants (has rejected nappies), and all his trousers are much too big, so they fall right down, giving him terrible builders bum, and then he trips and falls over too. So I need something to keep the trousers up - needs to undo quickly (not a buckle) to make potty trips easy. Where should I look? Either online or real shops - I had a quick trawl and couldn't find anything suitable.