Several have suggested I use the bathtub, but though it's long enough, my cutting board would have to curl up at the sides, so the kiddy pool is a better option.
Re getting rid of all the fluff trapped in the cuts, I use sticky tape wrapped round my fingers, and I don't cut W&N on it any more, because that was the real culprit. W&N can be cut at least 4 layers together by ordinary dressmaking sized scissors.