I've just been reading about potty trainer PODS. Has anyone used them and are they any good? If so where can I but them in the UK? Apparently they're similar to a sanitry towel but when the child wets their pants it goes cold so they know they've had an accident. My little boy has mastered weeing but just won't poo on the potty or toilet would PODS be any good to try and get him to poo on the loo???