As someone who knows absolutely nothing about music, I am close to admitting defeat on this one. Having (eventually) completed the grid, I have the following sequence of potential notes, starting at 1 and going clockwise - C, C, A, B, C or E, E, D or G, E or G, C, C, A, B or E, C, G, F or G, C, E or G, G, C, E, G, E or G, C, E, A or D, C or E, E. I also have 5 radials where there are no potential notes. Google indicates a sequence beginning G, B, B, A, C, B, G which I cannot accommodate anywhere. Also this sequence eventually requires a fifth note, so it must be wrong. Could some kind soul please point me in the right direction