Mr G? If so, we've mutual friends.
It may only be in old films that I remember, but RAF mess booze-up scenes would often feature a squadron member who was talented on the keys for a song-song. Probably a WWII thing when many personnel had learned at home, in the 'golden age' during the 1930s, how to play by ear on the ubiquitous parlour piano. It's a skill among 'untrained' pianists that's long since gone.
Guitarists? Well, that's a different matter - a post-war phenomenon we all know the results of.