As usual rich vocabulary and diverse clue styles… love the original word in 23d … grrrr
( )* = anagram { } = omitted < = reversed
Across
1 Breaking out, overturned old wall in prison?
ERUMPENT MURE< PENT
7 Covering bottom when rolling over
TARP PRAT<
10 High card? Chap holds nothing
MANILLE NIL in MALE
12 Be positive, or vacillate, without leadership
AVER {H}AVER
13 University in difficulty: board backs producing subatomic particle
NEUTRETTO U in NET OTTER<
14 No water flowing back in geological period
AEON (NO EA)<
17 Tree recoils, bent in storm
BRISTLECONE (RECOILS BENT))*
18 Indicator of chap’s old school is wasted in Gordonstoun
HISTIE HIS TIE
20 French are the same about copper coin supplanted by euro?
ESCUDO CU in ES DO
21 Recalled a weapon involving German war machine
ENIGMA G in MINE< A
23 Independent setter’s in order expressing gnostic belief
OPHISM PHI’S in om
24 Tungsten in time implicated by those destroying Dutch scientist
VAN DER WAALS (W in ERA) in VANDALS
26 Charge about pound for bolt
FLEE L in FEE
29 They back engineers and scientists penning some lines
REVERSERS VERSE in RE RS
30 I feel bad twisting bones
ILIA I AIL<
31 Skip counter manoeuvres
TROUNCE COUNTER*
32 Scottish Herald just switching sides?
LYON ONLY moving L
33 Distance measurer certainly used by English in conflict
WAYWISER (YWIS + E) in WAR
Down
1 Female student spurning proposition
EMMA {L}EMMA
2 Fashionable man’s inclination to roam
RAKE triple definition
3 Nasty rough inns depriving travellers of rides
UNHORSING (ROUGH INNS)*
4 Testing with hammers? Trees simply ruined
PLESSIMETRY (TREES SIMPLY)*
5 Explain ditching more than half of cider: pure liquid required
ELUATE ELU{CID}ATE
6 Online story possibly lacking a sting…
NETTLE NET T(A}LE
7…story in audio identifying Chinese money
TAEL homophone
8 Dampens radicals, bringing in barrel
RETUNDS TUN in REDS
9 Genetic expression of memory in a fruit
PROTEOME ROTE in POME
11 Parrots were mistaken for another bird
TREESPARROW (PARROTS WERE)*
15 Favours dipping pipe , without question, in broth
BOUILLONS {Q}UILL in BOONS
16 Kid always catching endless cold? On the contrary
CHEVERIL EVER in CHIL{L}
19 Any line may be scribbled without content
INANELY (ANY LINE)*
22 Nobleman shaved a bristle
ARISTA ARIST{O} A
23 Old King leaves sanctuary, showing wisdom?
OWLERY {GR}OWLERY a retreat for times of ill humour
25 Produce lambs, certainly not overlooking last two
YEAN YE{S} AN{T}
27 Behold executive committee also getting a boost?
ECCE EC EC<
28 Some bore getting up?
EGER boRE GEtting<
Thanks, Jed, and Beelzebub. I read 25D just slightly differently as YEA (certainly) N(ot) ie overlooking the last two (letters)