Ho Derek, At last someone admitting to be older than me!
On this discussion about ear playing. My Dad could only play by ear and could faithfully reproduce any tune complete with all correct chords. He played using mainly black notes (probably Fsharp) cos he said it was easier. Most of us would I suspect shyaway from that key. I can only play from a score, altho I can pick out virtually any tune on single notes pretty accurately (as I suspect most, if not all of us can do) but cannot find the appropriate chords, so I would guess that most ofus are earplayers in that sense. The lucky ones, like my Dad, can just do it properly without knowing how. On the other hand I believe that in music colleges the students are taught to improvise, which in my book is playing by ear. Some years back I bought a couple of books promising to teach me to play by ear but it didn't work for me. Perhaps I didn't try hard enough or am just too thick.....
What puzzles me is how blind pianists manage. I remember an American concert pianist ( think it was Alec Templeton or something similar)back in the forties playing the complete Rhapsody in Blue with orchestra. George Shearing, blind from birth, can compose, play any tune and obviously improvise. And I remember a blind piano tuner I once knew who was also a pretty good player.
As I said I can only play with the score in front of me. Simply can't remember the music and wish that I could,and that I could improvise and play like Peterson, Garner, Shearing et al. Perhaps in the next life???

Peter