Cryptic crossword No 3,849

Thanks for the grid! Favourites 4a 6d 13a. Caused myself a lot of trouble - had an I at the end of 20a for a while, and figured out 17 first and that let me to put DOE in 2d. D'oh! 14a i think i expected "naked" to be "without clothes" as in removing the outer letters, not the other way around, and I needed to read how 23a worked. Got 5d from crossers and backfit the clue. Fun theme and great grid fill to squeeze that all in! 18d and 16a are both WILD hahaha

Tvm Sisyphus. Wow! Found this v tough, made harder by lack of enumerations for the themed "clues"; but once I'd worked out what 3d must be, and done some sneaky Googling, most of it started to come together. Fave clues 9a, 10a, 16a (lol), 19d, plus 13a which took forever to work out but is fab! The "overall" formula in 4a was new to me but the solution was fairly obvious, and I don't get 21a (where do the swimmers come in?) but I'm sure that'll just be me being thick. But "overall" v good!

Thanks Sisyphus. I found that tough with the SI's meaning little until several crossers of 5d were in and I experimented with a few guesses. I didn't get 14a with the obscure instrument reference until the end, again from crossers. I wasn't familiar with the use of 'overall' in 4a, so that's for future reference. 21a and 13a I couldn't parse and needed your notes. There were several very good clues I picked out such as; 13a(clever), 11a, 25d, 8d and 26a though I have a query for 26a.

Wow Sisyphus, that was a struggle! I didn't really address the instructions at the start, but when I went back to them half way through I saw what 5d etc must be, which helped. Had a couple of false starts (2d and 21a) which needed correcting after checking the words- not aware of Uncle Jim's nursery rhyme! Favourites were 4a, 10a, 11a, 14a (modified version) and 8d. (Spent a while wondering how to fit chateau in 8d! Great idea, and lovely grid without any obscurities. Well done.