Across:
8 It's a concern for one making cuts (hair is a concern for barber = H- AIR) holding onto good books (Old Testament = -OT) (HOT AIR) or is that just empty words? (HOT AIR),
9 Is amicable (FRIENDLY) to opening 15 across (opening ‘friendly rivalry’ = FRIENDLY),
10 Ends embargo around island business (ends ‘embargO arounD islanD businesS’ = ODDS) – what’s the chances of that? (ODDS),
11 The stars (PROVIDENCE) for a port, that’s capital? (port and capital of Rhode Island = PROVIDENCE),
12 All hell broke loose (UPROAR), as there’s no metal in plate armour (there’s no ‘metal’ in ‘plate armour’ = parour = UPROAR),
14 One of the Freedom Fighters (resister) vocal (= homophone indicator) (‘resister’ = ‘RESISTOR’) on the circuit (on the electric current = RESISTOR)
15 Match (FRIENDLY) is a source of discord (RIVALRY) (FRIENDLY RIVALRY) or good-natured competition? (FRIENDLY RIVALRY),
18 Loud music (forte = -F-) from a German (‘a’ German = -EIN-) in restaurant (CAF-E) (CAFFEINE) will keep you awake at night (CAFFEINE),
20 Shipmates ignore map (‘shipmates’ ignore ‘map’ = shites = THESIS) produced by scholar in final year (THESIS),
22 Suddenly appeared (BROKE COVER) to have no money (BROKE) in Cobh (Cobh), it’s said (= homophone indicator) (‘Cobh’ – ‘cove’ = COVE-) – right (-R)? (BROKE COVER),
24 Lay figure puts out a fire (‘lay figure’ puts out ‘a fire’ = lygu = UGLY), as it’s not much to look at (UGLY),
25 Overturned (= reversal indicator), for example (e.g. = -GE-), submerged in case (in case) prepared (= anagram indicator) (in case = A-NCIES) (AGENCIES) by Governmental groups (AGENCIES),
26 Figure on the invoice (AMOUNT) for Pinot from mountaintop (‘Pinot’ from ‘mountaintop’ = mounta = AMOUNT).
Down:
1 House of Lords leader's ('House Of Lords' leaders = HOL-) party (Democratic Unionist Party = -D-UP) (HOLD-UP) offering to delay (HOLD-UP),
2 Counters (BARS) leaders of Blue and Red States (leaders of ‘Blue And Red States’ = BARS),
3 Steadied oneself (PREPARED) as pressure (P-) is to get par (-PAR-) stuck in high grass (reed = -RE-ED) (PREPARED),
4 Shocking big do (AFRO) – even bad for you! (even letters of ‘bAd FoR yOu’ = AFRO),
5 Receptionists missing Preston (‘receptionists’ missing ‘Preston’ = cetiis = CITIES), Manchester and London, for example? (CITIES),
6 Make light of the fact (UNDERSTATE) it’s below (UNDER-) New York, for one? (-STATE) (UNDERSTATE),
7 Everything (ALL-) is free (-CLEAR) (ALL-CLEAR) and you can’t get any better than that (ALL-CLEAR),
13 Unique (ONE OF A KIND) novel? (ONE OF A KIND),
14 A measure of frost, for example (poet Robert Frost / RHYME), in Limerick (limerick RHYME),
16 A rare dog (a rare dog) barking (= anagram indicator) (a rare dog = ROAD RAGE) drives people mad? (ROAD RAGE),
17 Travel in (travel in) train (= anagram indicator) (travel in = INTERVAL) for theatrical break with refreshments perhaps (INTERVAL),
19 Is (IS-) going to church (-CH-) institute (-I-) and academy (-A) (ISCHIA) with one of those off Naples (ISCHIA island west of Naples),
21 Christmas (Christmas ISLAND) in 19 down, for example (‘Ischia’, for example = ISLAND),
23 Advertise leaving out tired (‘advertise’ leaving out ‘tired’ = avse = VASE) jar of flowers (VASE),
24 Half the food (half the ‘FOod’ = -FO-) in America (US = U-S) (UFOS) produced by crafty types, the subject of conspiracy theorists (UFOS).