I'm a cheater and use sposies at night, but have had lots of experience of sensitive skin with my daughter in her daytime cloth - not chafing per se, but you only have to whisper the word "rash" and she comes up like a lobster! Metanium is good to get it healed, but I also found Morhulin good when it was red and angry-looking (contains cod liver oil), and when all else failed (which happens still, now and then, or when teething rash attacks) Daktacort for a day or 2, sparingly, gives it a chance to heal quickly. It's available over the counter as well as on prescription - we first had it on prescription when nothing else would work. It's a steroid cream, so not ideal, but I'd rather use this infrequently than have her suffer with angry red, raised welts on her bum that won't clear for weeks.
Once her skin's good again I use Metanium everyday cream, or vaseline as a barrier, day and night, every nappy change....works well for us. The Metanium everyday is fab!
My dd is nearly 11 months and is 23 lbs and wears WNNN for bed with either wool of fleece and just recently within the past 2 weeks she has had some horrible red chafing on her thighs. We do nappy free time as much as possible and use cj's like it's going out of style but nothing seems to be working. Her nappies during the day are fine (mostly ittis) and I feel like we have tried everything and nothing will work. So any suggestions or ideas please share as her poor little thighs are quite red and sore and I really REALLY don't want to have to use sposies at night. Thanks xx 
