Tried to buy a blow-torch head from Screwfix the other day. It's gone all, "Have to order it on the web." to which my reply was, "No thanks. Good-bye."
I can eke a few more uses out of those I have so I daresay by the time I absolutely need new brushes they'll be back in stock.
I'll have a dekko in one of the independent(ish) hardware shops tomorrow, see if they've got any.