Jon - you don't have children, do you? (if you do, I eat my worms ....) Then you'd know that they constantly demand food & drink. Elevenses and tea are required for the sanity of the parents. However, I would say, with a big "full english" under their belts, having stayed in a b&b, the demands can be substantially reduced....
I just don't think Elevenses for 4 has to cost ?20. I bet if you tired you could manage to get Elevenses for 4 for ?10 - I've just halved your bill!