Done, dusted by Monday night - not bad for me.
Very clever construction - thank you, KevGar - which was very daunting at first, but got rapidly easier as filling progressed, largely thanks to the Chambers app.
The extra word cross-checking, once the thematic penny had dropped, was useful, but not absolutely essential to complete the thing; for instance, I'm still totally baffled by 12d and have no idea what the answer to the clue or the thematic object, either added or removed, could be - although everything else works and I'm sure the grid entry is robust.
Also, 35a doesn't appear to have a definition - unless it's some kind of obscure &lit; and I can't find any meaning for the complete answer; the thematic object removed to give the actual entry at 35a doesn't appear in Chambers, and
actually also commonly means something extremely rude in another language. But the extra word cross-checking confirms that there's only one solution.
Some hint on both these answers would be nice, but now only of academic interest.
But lots of nice words, some new to me, so thanks again, KevGar.
Setter takes exceptional material sacrificing length for general intelligence.