Cryptic crossword No 3,123

Tremendous fun. Very impressive how you sustained the theme in so many of your clues. Yes, quite a few here were difficult - 'crunchy' I call them, but half the fun was reverse-engineering the parsing. I only now got where the DA came from in Derrida. Same as the Chlorine in Monte Carlo (why not Paris?) Far too many to call out but love the straight of 19d (given the theme!) 7a and the Spoonerism in 25a. Purists might call out the indirection of 10a, (anagram of a synonym) but didn't mind it.