I think they get the same fee no matter how long they are on for, like Simply. As for the haven't cooked for xxx years, a) I guess when invited to do the show they have tome to practice if they want to, b) its not too difficult to resurrect old skills c) Cooking techniques can be learnt, presentation is harder but can be learnt, especially if you are naturally neat and have a design eye but having a palate and knowing how things taste is the invaluable bit and very difficult indeed to learn.