[MGlatte]

This isn't going to help you, but could it just be really smelly wee? Caelan, at times, has really smelly wee. I (and anyone nearby) can smell it as soon as he wees and it doesn't matter what fabric is on his bottom or how the nappies have been washed.

I have started washing his nappies in the late afternoon and hanging them out on the line overnight and all the next day. I haven't noticed the smell since I've been doing this. But I'm not sure whether I've solved the problem or if he is just not doing smelly wees at the moment.