Two hours in on Friday evening I thought I was going to finish in record time for me. Theme words, clue types, name all identified, clashing cells located and resolved and just half-a-dozen clues to complete which I thought would be a matter of minutes. Wasn’t able to look at it yesterday, but I think it’s taken me another three hours to finish off.
Still a couple of definitions that puzzle me, although I’m sure I must have them right:
7d - Definition in clue points to a person. Wordplay seems to lead to something that person might use rather than the person
18d - I’d be more comfortable with my answer if the definition included the word ‘unaffected’ rather than ‘affected’.
And given the precise words used to identify the theme, I’d have thought ‘You must have one or the other’ would be a technically more accurate title than ‘you can’t have them both’!
But small quibbles. Generally very enjoyable and challenging to finish off.