1. Term linked to endless scrawl, and RIP possibly? It’s not so terminal! WRITER’S CRAMP (anag. less l) A fine semi-& lit. surface. Dr Watson wonders if it’s possible to use the ‘not terminal’ in place of ‘endless’ to make a full & lit.
16. Ditch job in Oz, good split GRIP (g rip, 2 defs.) Azed exploits some Oz slang and a rare and distinct meaning of ‘grip’ to enhance the clue’s surface. The clue might have worked quite well without the final piece of wordplay.
20. Allure and experience surrounding Wellington, according to Boney? SEDUCE (Duc in see) Dr Watson has confirmed that Wellington was elevated to a Dukedom before he encountered Napoleon at Waterloo.
24. Metrical form, hybrid, having to conform to its rules outwardly? SCAZON (zo in scan) The wordplay references the definition, as a scazon would need to scan. The first zo, zho, or dzo of the crossword year.
28. Magic one conceals this sprite maybe ICON (hidden) A sprite in the computer graphics sense is a type of icon.
31. Polished ——? May be seen in Daphnis and Chloe, i.e. spinning CHAÎNÉ (comp. anag. & lit.) A reference to the ballet scored by Ravel provides the context for the chaîné move, which involves multiple turns.
34. Tiresome chat recalling one period over and over again YADA YADA YADA (a day, rev., repeated) Full marks to Azed for slipping a most unusual entry into the bottom of the grid.
4. King off the fizz, King retaining energy for sport RUGGER ((K)rug + E in GR) Some well-heeled solvers may have been dropping their Krug empties into the recycling recently, so the reference will be familiar. Dr Watson noticed that with a slight variation in wording this could also have made a clue to SOCCER (soc(k) + E in CR).
5. Fine instruments? Composer must have died for us STRADS (d for us in Strauss) A beautifully penny-dropping clue.
9. All women getting happiest (mostly) when excited about features of parapsychology PSI PHENOMENA (no men in anag. less t) It takes a few moments’ thought to see how ‘all women’ contributes to the wordplay.
19. Some dragonflies chase flies – name one AESCHNA (anag. + n a) The clue’s wording cleverly misleads from the anagram, creating something that looks like it might be hidden or & lit.
25. On quitting Jerusalem, Italian consumed pasta ZITI (It in Zi(on)) Ziti is a tubular form of pasta, no doubt available in some parts of Jerusalem at least.
Across: 10. HAIRCUT (air c in hut); 11. HYPOS (‘high pose’); 12. I CHING (i(t)ching); 14. RADE ((pa)rade); 17. KENTLEDGE (anag. + l, all in kedge); 18. YAGGER (anag. inc. G); 21. FEMORA (’em in for a; see femur in C.); 26. SIMPATICO; 30. NAIN (Nai(r)n); 32. KNELT (k(I)ne l(I)t); 33. TEXTMEN (m in anag.).
Down: 1. WHISKY-FRISKY (whisky Fri sky); 2. RACHE (h in race); 3. TRIO (t to start in riot); 6. CHARGE-CAP (anag. in chap); 7. APERÇU (per. in a Cu); 8. MORISCO (is c in anag.); 13. HANG (hidden); 15. CLERICITY (l eric in city); 22. MOONED (one in Mod1); 23. AMENTA (men in ’at + a); 24. SPICED (I c in sped); 27. CONED (on in ced(e)); 29. MATY (initial letters).