Tatters, that looks right to me! The A is from the clue and then there's a 'key', quite often used by crossword setters. I've just touched mine now....
All done and feeling chuffed that I managed it with only a couple of references to Mrs B towards the end.
There’s only one clue I’m struggling to parse and that’s 43a... I’ve got the misprint and understand the wordplay, but I can’t really see the definition.