if you are prepared to post where you are (roughly) someone may know of a place that stocks it. I’m pretty sure both playfull toys (bristol) and steiner house (london) have stocks, so does our local independent art shop (cardiff)
Alternatively, i can talk you through dyeing your own with food dyes. You’d need plain or pale 100% wool, which you probably could get from somewhere today. At a pinch I’ve knitted with wool before its dried, its not ideal but tbh for a toy it won’t make a huge difference (its more not that nice for you really)
Not clear if its knitting wool or roving you are after?
ETA sorry, reread post. fairy wool to me is multicoloured stuff. Sounds like you just need some fleece? The thing is, there is no post today, else I’d be happy to put a bit in an envelope to you-but it would not enter the postal system til tommorrow and with christmas post wouldn’t get there in time. Think you need a bricks and mortar shop or a local GPer. Could you use something else temporarily? If you have another colour roving? If you have another colour, like I say I could talk you through dyeing it darker, brown would be really easy as you could do it with tea and vinegar.