Across:
1 Signs of indifference (SHRUGS) in a line from languishers (‘a line’ from ‘languishers’ = gushrs = SHRUGS),
4 Loss of nerve (COLD FEET) in Cork (C-) is nothing new (-OLD) for those going walkabout perhaps (FEET) (COLD FEET),
9 Provoke (INCITE) dietician to release aid (‘dietician’ to release ‘aid’ = ieticn = INCITE),
10 Opens to a (opens to a) knock (= anagram indicator) (opens to a = TEASPOON) from one of those capable of causing quite a stir (TEASPOON),
12 Many French monarchs had this name (18 Kings of France called LOUIS-) for a fair amount of (half of) Indian (half of ‘indIAN’ = IAN-) area (-A) (LOUISIANA) on Texas border (LOUISIANA),
13 Love bites best ignored (‘love bites’ ‘best’ ignored/without ‘best’ = lovei = OLIVE), as that one’s a bit green (OLIVE),
14 Those hoping to take seats for the party, unofficially (GATECRASHERS) open 18 across (open ‘gate receipts’ = GATE-) at Conservative (C-) Breakfast for meat consumers (-RASHERS) (GATECRASHERS),
18 Notes taken at theatrical venue perhaps (notes/money taken = GATE RECEIPTS) handed over by those in attendance (GATE RECEIPTS),
21 To sum up (RECAP), offers blow (R-AP) over ecstasy (-E-) at college (-C-) (RECAP),
22 It’s about (RE -) vet (vet/study = -EXAMINE) (RE-EXAMINE) in study again (RE-EXAMINE),
24 Uncover (DREDGE UP) revolutionary (-RED-), for example (e.g.), rising (= reversal indicator) (e.g. = -GE) in party (Democratic Unionist Party = DUP = D- UP) (DREDGE UP),
25 First episodes (PILOTS) with spoilt (spoilt = PILOTS) models (= anagram indicator),
26 Tries for a part (-READS) after (= positional indicator) writing (from 3Rs = R-) Alien (-ET-) (RETREADS) and the more grippy parts of The Transporter? (tyres = RETREADS)
27 To have let it (LEASED) – cheered up (pleased) heading off (p) (‘pleased’ without ‘p’ = LEASED).
Down:
1 Wise woman (S-AGE) protects Tablet (-PILL-) (SPILLAGE) when her pint ends up on the floor (SPILLAGE),
2 Narrates (RECOUNTS) introductions for radical editions (introductions for ‘Radical Editions’ = RE-) and that matters (that matters/counts = -COUNTS) (RECOUNTS),
3 For those departing flighty types (GATES) with one-third of 14 across (one-third of ‘GATEcrashers’ = GATE-) from society (-S) (GATES),
5 Finished (OVER-) with a (-A-) Greek character (-CHI-) always (-EVER) (OVERACHIEVER) the one exceeding expectations (OVERACHIEVER),
6 Education programme (-COURSE) for detectives (Dis = DIS-) open (= position indicator (DISCOURSE) to debate (DISCOURSE),
7 Strikingly unconventional (EXOTIC) engineering (E-) associated with toxic (toxic) mixture (= anagram indicator) (toxic = -XOTIC) (EXOTIC),
8 Loving (TENDER) proposal? (TENDER),
11 Motorcade (PARADE) for Clay? (GROUND) (PARADE GROUND) Those trained to fight are expected to leave their stamp on it presumably! (PARADE GROUND),
15 Cold (C-) pig meat (-HAM-) from Gulf (gulf = gap = -PAG-) served up (= reversal indicator) (gap = -PAG-) with a fair amount of (half of) undiluted (neat) (half of ‘NEat’ = -NE) (CHAMPAGNE) drink (CHAMPAGNE),
16 Rips coat (rips coat) playing (= anagram indicator) (rips coat = APRICOTS) in the orchard (APRICOTS),
17 Had the measure of (ASSESSED) fool (ASS-) spilling (= anagram indicator) seeds (seeds = -ESSED) (ASSESSED),
19 Museum display of Socialist Realism, for example (Red Art), set-up (= reversal indicator) (red art = TRADER) by dealer (TRADER),
20 Don’t object to (ACCEPT) performance (AC-T) covering Coldplay’s first (‘Coldplays’ first = -C-) record (Extended-Play record = -EP-) (ACCEPT),
23 It’s odd coming off side-road (‘odd’ coming off ‘side-road’ = siera = ARISE) in that get-up (get up = ARISE).