Thanks for the advice re nappies and leaky pooh chaps, much appreciated. Thankfully it's fairly obvious when she is having a poo so it is generally possible to take action promptly to prevent leakage, but on the occasions when it isn't detected it goes everywhere (over the nappy up her back, up her tummy) and of course she is kicking away and the poo gets all over her legs, feet and me, which is fun.