Glad I persevered with this as it is a very clever puzzle, but without the generous help from those on this forum I wouldn't have come close to finishing this.
I would concur with smellyharry's comments - I'm not particularly good at cold solving clues of this complexity, and therefore rely on crossing letters providing additional pieces of the puzzle. For me, this week and last week have brought an end to a decent streak of Listener successes.
Despite having a completed grid and end game, I'm still struggling to parse a couple of the clues. Perhaps someone could give me a hint on how 42A and 46A work? I had taken 42A to be a 3 letter word for 'See' around 'M', but I do not see how the 3 letters I have are a synonym for 'see'.