Cryptic crossword No 3,260

This crossword (and its theme) came about entirely because I devised the clue at 20A one night in bed. Spoilery explanation of theme in replies for when you're done...

Great stuff, right in my comfort zone. I didn't spot the theme but I admired the ridiculousness of the clue for 20a. Also really enjoyed 9a, 18a (what a surface!) and 21a.

Hi yogdaws, I thought this was a nice puzzle at first, but after researching the theme I thought it was exceptional! Of course 20a would be an editor’s nightmare but it’s a goldmine of hidden nuggets. In their own right I particularly like the following clues: 7a, 18a (very neat!) 20a (crazy but unarguable), 4d, 17d, & 19d. Many thanks! Spoilery bits below…

I’ve only solved 20a so far but you get a Like ❤️ for that alone 😆

One of those puzzles where everything makes sense on reading your comments below. 20a is the star clue and, whilst I have seen both translations, they had vanished from memory so it was nice to be reminded of them. A very interesting basis for a puzzle. Over and above the star, 8a, 13a, 21a my podium. Well done. Thanks. PM

I enjoyed this - thank you! Faves were 8a, 9a, 20a of course, 23a, 3d, 16d, 19d (took me some time) and 23d. Spoilers below