Was thinking about this when I did a nappy wash today. BG's point about the direct contact with laundry tabs causing the colour run just isn't true , I don't ever use laundry tabs on nappies, so there is no direct contact, and it still happened to mine.
I haven't gone to BG about it, as it doesn't really bother me, they're just creche nappies and tbh I don't care what they look like once they're clean