Len,
Sorry to hear of you problems and intention to give up modelling. As others have already said, try and find a way to carry on. I know 4 mm stuff takes up less room than 7 mm, but for years I just worked on a tray on the dining table. OK, hand tools only, but I managed to build several locos that way. Admittedly, I had a very understanding wife, who allowed model bit to lie around without having to clear away after every session, but I'm sure you could negotiate a similar concession.
Hope you resolve the problem and manage to carry on.
Dave.