but the price is different for the room rather than the number of people, they're charging me less for a room with two beds and one person than a room with one bed. it's all sensible prices nomally, but only the twin room comes under the early booking discount, that's where the lower price comes in.
ah well, it's all booked now, seems I have a spare bed, but noone to go in it, because I only booked for one person rather than two.