Overall I didn’t think this was as difficult as some Dogberry puzzles. It seemed to be something of a mixture, some very easy clues, some more tricky ones, some good surfaces and some that didn’t make much sense (at least to me). I rather liked the wordplay in 9dn.
Across
1 WOBBLE B (bishop) in ELBOW (joint) reversed
4 KINDLING KIND (genus or species) LING (fish or shrub)
10 ROEBUCK CUBE (solid) reversed in ROK (South Korea, IVR)
11 DORMICE DO (cook) M (large number) in RICE (staple food)
12 RAKE [d]RAKE (bird losing head)
13 GINGIVITIS GIN (spirit) VI (six) in GIT (fool) IS
15 BROLLY ROLL (piece of bread) in BY
16 ANATOMY NATO (alliance) in AMY (girl)
20 UNCOUTH O (love) in UNCUT (having escaped censorship) H (hot)
21 AVIARY A I (setter) in VARY (change)
24 THUNDERBOX *(DETOX BRUN[c]H)
26 SWAP PAWS (feet) reversed
28 MEMENTO ME (compiler) in MENTO[r] (finish off teacher)
29 ELEGIST LEG in [h]EIST (‘old-up)
30 CONTRITE CON (internee) TRITE (lacking originality)
31 STEELY EEL (fish) in STY (enclosure)
Down
1 WARDROBE EBOR (archbishop) DRAW (pull) reversed
2 BREAKDOWN dd
3 LOUT L (student) OUT (away)
5 INDIGENT GI (soldier) revered in INDENT (space)
6 DERIVATIVE ER IV (Queen Elizabeth the Fourth) in DATIVE (case)
7 IDIOT DIO (god in Italian) in IT (Italian)
8 GREASY GR (Greek) EASY (simple)
9 SKEIN E (drug) in SKIN (intradermal)
14 BLOOD DONOR B ODD (rum) in LOON (bird) OR
17 MEANWHILE MEAN (signify) WHILE (whereas)
18 START OUT STAR TOUT (renowned salesman)
19 SYMPATHY *(MYTH PAYS)
22 ATOMIC hidden in ‘mantegnA TO MIChelangelo’
23 TOWER dd
25 UNMAN M (male) in UNA (woman) N (name)
27 REST dd
Thanks Gaufrid
I think my favourite part of this puzzle was the definition for DERIVATIVE: “betraying debts,” which had me stumped for a while.