So I nearly finished the crossie yesterday (Guardian, obviously).
I was defeated by one clue ...
25a. A good time for the larks? (11) A _ L _ O _ L _ D _ Y
I started to look at my "crossing" answers, thinking they must be wrong.
And it turns out the answer was ...
ALL FOOLS DAY
I mean, come on ... RE FE REE !!!
That is so totally out of order.
(you see what I did with "referee" there ... splitting it into 3 words, like the clue ... because that's how you say "referee" when you're frustrated? okay okay, never mind)
The theme is geniuses (24a), and in particular the Guardian's most famous setter(24d) who is 9a today.
His pseudonym can be found in grid, step wise down
A
R
- AUC
--------A
--------R
---------IA