I took this out of the library on a permanent basis in the early eighties. A collection of short stories- I can remember one being about several favours of ice cream and the odd one about a teenager whose dad secretly joins a rock band where they dressed up as elderly folk on zimmer frames and were a huge hit on TOTP etc. The song went "I'm so old I'm falling to pieces, all my skin is lines and creases" I can remember that but not the book title.
Also around the time a novel about gymnasts which was a bit dark-broken legs etc and eating disorders.
Any clues?