Across
1 Salt and piece of food left on top of oven before tea prepared (11)
ORTHOBORATE; ORT-HOB-OR-(tea)*; before=OR;
11 Scots relished it with wine (5)
SARED; SA-RED;
12 Spirit that’s immature, so to speak (4)
WILI; the maiden spirit in Giselle; can’t see the cryptic
13 Row about movie expressed in three lines (7)
TIERCET; TIER-C-ET;
14 One chum going round put on second stone! (5)
LAPIS; I-PAL reversed-S; second=S;
16 Mineral and iron bar left inside (7)
FELSPAR; FE-L-SPAR;
17 Singer holds current map for South American plateau (9)
ALTIPLANO; ALT(I-PLAN)O;
18 You bet two pounds, for example after one (6, two words)
I’LL,SAY; I-LL-SAY;
20 First person supplanted by European in monotony of Latin hymn (6, two words)
TE,DEUM; monotony=tedium and replace “I” by “E”;
22 Send wettest shortened messages (6)
TWEETS; (wettest-t)*;
24 Hard to get Cliff to join church (6)
SCARCE; SCAR-CE;
26 Agitation reported, half of Doha beginning to march in Qatar perhaps (9)
SHEIKHDOM; sounds to some like “shake”-DO(ha)-M(arch); tough if you say “sheek” as in the old song “The Sheik of Araby”;
28 To be liable to a tax initially given by region (7)
ATTRACT; A-T(ax)-TRACT;
30 Corps support Montgomery perhaps (5)
CLIFT; C-LIFT; corps=C; reference US film star 1920-1966 best known in From Here to Eternity;
31 Manage to get a letter from Athens in front of first lady (7)
ACHIEVE; A-CHI-EVE;
32 Calm kid pulling face (4)
EASE; (t)EASE;
33 Millions are right about name of police district (5)
MANOR; M-A-(N-O)R; are=A; name=N; of=O;
34 Special treatments implicated tax official in East Kilbride (11)
STENTMASTER; S-(treatments)*; special=S
Down
2 Fast Papa has gone bust (4)
RAID; RA(p)ID; papa=P in phonetic alphabet;
3 Negotiate about splitting a pony (5)
TREAT; T(RE)AT; pony (Indian)=TAT;
4 Glorify Maggie’s composure after losing power (7)
HEROISE; HER-(p)OISE; a reference one presumes to Margaret Thatcher;
5 Robust nets end in downfall for nectar-eating insect (6, two words)
BEE,FLY; BEEF(L)Y; L from (downfall)L;
6 Consume more than every other character in yogurt repast? (6)
OUTEAT; hidden (y)O(g)U(r)T-(r)E(p)A(s)T;
7 Jumpers kiss sexily in large car (9)
ROLLNECKS; ROLL(NECK)S;
8 Trick on wharf is smarter (7)
TIPPIER; TIP-PIER;
9 Ogle ideal boobs (5)
ELIAD; (ideal)*;
10 Forget side out to restrict runs on leg (11)
DISREMEMBER; (side)* contains R=runs – MEMBER;
11 Prudish characteristic left one drifting without a date (11)
STRAITLACED; S(TRAIT-L-ACE)D; can’t see how “drifting without a date” works;
15 Advanced course not one to be taken up from this outdated description (9)
APATHATON; A-PATH-(NOT-A reversed);
19 One set term for Michael Foot could be this (7)
LEFTIST; (I+set+L+ft)*; L from (Michae)L; ft=foot;
21 Bloomers? Pilot owned up (7)
DAHLIAS; SAIL-HAD reversed;
23 Cutting dry old schoolmaster, semi-retired (6)
SECANT; SEC-ANT; no idea who the old schoolmaster might be;
24 Friends perhaps enter shortly after rest (6)
SITCOM; SIT-COM(e);
25 One hugely burdened eventually taking time off (5)
ATLAS; AT-LAS(t);
27 Once went under medic on hospital department (5)
DRENT; DR-ENT; old word for drowned;
29 Frenzied shout from eBay! (4)
EVOE; E-VOE; bay=VOE;
Edited at 2017-05-28 10:45 am (UTC)
Can’t say I think much of WILI
I agree with mohn2 on 11dn.
There is a typo in the blog in the answer given for 19 down.