Across:
1 Issues (TOPICS) with competitors not taking metro (‘competitors’ not taking ‘metro’ = copits = TOPICS),
4 Dijon’s (Dijon’s MUSTARDS) revolutionary informers (rats = -STAR-) found in wet ground (mud = MU-D-) shot in the head (‘Shot’ in the head = -S) (MUSTARDS),
9 In order to remove Don (‘in order to’ remove ‘Don’ = irerto = RIOTER) from The Mob (RIOTER),
10 Likely to work (FEASIBLE) with American (-A-) consumed by strange (= anagram indicator) beliefs (beliefs = FE-SIBLE) (FEASIBLE),
12 Presumably, this limits the number in educational establishment (SCHOOL CAP) or in a classy outfit? (SCHOOL CAP)
13 Sounds like (= homophone indicator) something you’d get from The Treaty (get ‘peace’ = ‘PIECE’) and The Queen (PIECE on the chessboard),
14 Notes (MUSICAL SCALE) Annie (Annie = MUSICAL) has a job at the bar (Senior Counsel = SC-) providing something for the drinkers (-ALE) (MUSICAL SCALE),
18 One of The Stones (ROCK) and Fat Elvis (Fat Elvis) playing (= anagram indicator) Fat Elvis = FESTIVAL) (ROCK FESTIVAL) Woodstock? (ROCK FESTIVAL),
21 Oscar, for one (AWARD in film), gets a (A-) place in medical institution (-WARD) (AWARD),
22 Allotment (ALLOWANCE) permit (ALLOW-) for area (-A-) near back garden (back/rear ‘garden’ = -N-) and church (Church of England = -CE) (ALLOWANCE),
24 They’re bound to sell (BOOKS-) on a short trip (-HOP) (BOOKSHOP) to a novel place? (BOOKSHOP),
25 Network (LIAISE) of Israelites not taking rest (‘Israelites’ not taking ‘rest’ = ialies = LIAISE),
26 Lyric, etc., (lyric etc) rewritten (= anagram indicator) (lyric etc = TRICYCLE) as a vehicle for the little ones (TRICYCLE),
27 Puts on (STAGES) school (-S) gates (gates) – wobbly (= anagram indicator) (gates = STAGE-) from the start (= position indicator) (STAGES).
Down:
1 Tax (TIRE-) on total amount (sum) reportedly (= homophone indicator) (‘sum’ = ‘some’ = -SOME) (TIRESOME) is annoying (TIRESOME),
2 Second sight (PROPHESY) of something Jeremiah said (PROPHESY of Jeremiah, the prophet),
3 Belief (CREDO) in some do-gooder covering (some ‘do-goODER Covering’ = oderc) up (= reverse indicator) (oderc = CREDO),
5 Out of the blue (UNEXPECTEDLY), organisation (United Nations = UN-) is due to arrive (-EXPECTED-) with what’s central to analysis (central to ‘anaLYsis’ = -LY) (UNEXPECTEDLY),
6 Presumably, this is to check if high-flyer is capable (TEST PILOT) to take flight from an exam? (TEST PILOT),
7 Run (R-) taxi (Uber = UB-ER) around far side of the suburb (far side of ‘suburB’ = -B-) (RUBBER) on the new types presumably? (RUBBER),
8 On reflection (= reversal indicator), needs to get to Bath badly (reeks = SKE-ER) over the start of the weekend (the start of the ‘Weekend’ = -W-) (SKEWER) for barbecue (SKEWER)
11 What one of the gravediggers has to do in Hamlet (gravedigger in Hamlet has to ACT LIKE A FOOL) with clown’s remit (ACT LIKE A FOOL),
15 Sunblock (CLOUD-) on body ultimately (body ‘ultimatelY’ = -Y) contains sun? (SKY) (CLOUDY SKY) One should know in a nebulous way it doesn’t stop rays penetrating! (CLOUDY SKY),
16 Time (-T-) in the latter half of the day (evening = EVEN-ING) (EVENTING) for the horsey set (EVENTING),
17 Poser (CLUE-) from takeaway (take away = -LESS) (CLUELESS) has no idea (CLUELESS),
19 Religious leader (RABBI-) has a bone to pick (-T bone) (RABBIT) in The Warren perhaps (RABBIT),
20 One (-I) taking shifts in the factory (rotas) arising (= reverse all indicator) (rotas = SATOR-) (SATORI) out of what the Buddhists say is enlightening (SATORI),
23 Women (W-) upsetting (= reverse indicator) teacher (sir = -RIS-) telling Head (‘Telling’ head = -T) (WRIST) to watch position? (WRIST).