Across:
1 Pressure (P-) on Alice (Alice) working (= anagram indicator) (Alice = -LAICE) (PLAICE) on takeaway menu (PLAICE),
4 Did a job on the numbers (ARRANGED) for a grander (a grander) model (= anagram indicator) (a grander = ARRANGED),
9 Illustrates lost trail (‘illustrates’ lost ‘trail’ = lustes = TUSSLE) in Donnybrook (donnybrook/row = TUSSLE),
10 They’re plugged in (ADAPTORS) to Pastor (pastor) freely (= anagram indicator) (pastor = A-PTORS) welcoming State prosecutor (District Attorney = -DA) (ADAPTORS),
12 The controversial issue (HOT POTATO) of The Duke of York (type of potato) presumably feeling the heat? (HOT POTATO),
13 Levels (EVENS) site from seventies (‘site’ from ‘seventies’ = evens = EVENS),
14 Church (Church of England = -CE-) warden (keeper = -KEEPER-) consumed by The Greens (peas = PEA- -S) (PEACEKEEPERS) – those presumably bringing two opposing Parties together (PEACEKEEPERS),
18 Resolving the conflict (PEACEKEEPING) for 21 across (‘peace’ = PEACE-) is not giving up (-KEEPING) (PEACEKEEPING),
21 State (= homophone indicator) component (‘piece’ = ‘PEACE’) doesn’t refer to The Troubles (PEACE),
22 Gets into rows regularly (OARSWOMAN) for pulling a few strokes (OARSWOMAN),
24 Bloodsucker (COUNT-) that is (that is= i.e. = -IE-) found on top of seedlings (on top of ‘Seedlings’ = -S) (COUNTIES) in Wicklow and Wexford (Wicklow and Wexford = COUNTIES),
25 Mates (BLOKES) of the menfolk? (BLOKES),
26 Watch (EYE-) golf (-G-) with young woman (-LASS) (EYEGLASS) – that’s a solitary spectacle? (EYEGLASS),
27 Stock market purchases (SHARES) of endless (end ‘lesS’ = S-) fast runners (hares = -HARES) (SHARES).
Down:
1 Step (step) up (= reverse indicator) (step = pets = PET S-) for small dances (-HOPS) (PET SHOPS) where you’ll find more than one of those in 2 down (you’ll find more than one ‘Alsatian’ in PET SHOPS),
2 Atlas in a (atlas in a) production (= anagram indicator) (atlas in a = ALSATIAN) produced by Frenchman (ALSATIAN),
3 Found in The Abbey (CELL-) on old (-O) (CELLO) musical instrument (CELLO),
5 Very popular (RED-HOT) game (POKER-) at school (-S) (RED-HOT POKERS) and growing particularly in South Africa (RED-HOT POKERS),
6 Granny Smith (APPLE TREE) is a cider producer (APPLE TREE)
7 The key (music key G-) to 22 across? It’s similar (‘oarswoman’ is similar to -ROWER) (GROWER) for one involved in a plot! (GROWER),
8 Piece of furniture (desk) that’s not finished (k) (‘desk’ without ‘k’ = DES-) first? (first = 1st = -IST) (DESIST) Give over! (DESIST),
11 In The Office encouraging gossip among those standing around (WATER COOLERS) with ice buckets presumably (WATER COOLERS),
15 Rudimentary (ELEMENTAL) ingredient (ELEMENT-) for a (-A-) starter of lasagne (starter of ‘Lasagne’ = -L) (ELEMENTAL),
16 Manufacturer of locks (WIGMAKER) has a job designing stuff that goes over many people’s heads (WIGMAKER),
17 Feels uneasy (AGONISES) as adaptation (= anagram indicator) is on ages (is on ages = AGONISES),
19 Tyro from apothecary (‘tyro’ from ‘apothecary’ = apheca = APACHE) grew up steeped in the adventures of Geronimo presumably (APACHE),
20 Flower (flower/river DANUBE) with ultra-blue heads (‘Ultra-Blue’ heads = -UB-) welcomed by Ophelia, for one (Ophelia in Hamlet = Dane = DAN-E) (DANUBE),
23 Clone from well-chosen (‘clone’ from ‘well chosen’ = welhs = WELSH) type from a neighbouring island (WELSH).