I would try washing. I’d be more concerned if it was on a mattress but less so on the side.
It doesnt look like mould based on this photo. Try wash it and see if it comes off xx
Thanks - it's just this single mark, no signs of anything anywhere else and my husband managed to basically remove it with a bit of scrubbing with a dettol wipe this evening (but if it IS mould I'm not sure that means he killed it?!). I'm so sure the mark wasn't there when it went into the loft which is why I'm stressed that mould is most likely! They do sell replacement fabric but for £50 which feels like not loads less than buying a new crib.
Personally I wouldn’t risk it. I bought new fabrics and mattress for mine from my first for this reason. Better to be safe and cheaper than buying a whole new snuz
@Aimee Thanks having slept on it I think that's what I'm going to do, clearly if I'm bothered enough to post this I'm likely to keep stressing about it if I try to just go ahead and use it!
It maybe worth contacting them and seeing if you can just get new fabrics 😊