Across:
1 Reserved (reserved/shy = DEMURE) object (object/protest = DEMUR-) reaches closing price (closing letter of 'pricE' = -E) (DEMURE),
4 Recent delivery (NEWCOMER) to novice (NEWCOMER),
9 An indulgence (LUXURY) producing milk and honey (LUXURY),
10 Rules, etc., (rules etc) affected (= anagram indicator) (rules etc = LECTURES) stern reprimands (LECTURES),
12 Pimlico (Pimlico) butcher (= anagram indicator) (Pimlico = -OMPLICI-) in court (Ct = C-T) (COMPLICIT) is involved with others in illegal activity (COMPLICIT),
13 Large (L-) antelope (gnu) raised (= reverse indicator) (gnu = -UNG-) by Zoo’s foundation (‘zooS’ foundation = -S) (LUNGS) found in a cage linked to air-conditioning unit? (LUNGS),
14 Change of mind leads (‘Change Of Mind’ leads = COM-) to written protests with signatures (-PETITIONS) (COMPETITIONS) and a number of fights in Ring, for instance (COMPETITIONS),
18 Mass gathering (CONGREGATION) of people from The Services (CONGREGATION),
21 Oversight (LAPSE) over (= reverse indicator) in Prince’s palace (in ‘princES PALace = espal = LAPSE),
22 Work out (CALCULATE) to achieve a figure perhaps? (CALCULATE),
24 Very sour (very sour) boss (= anagram indicator) (very sour = SURVEYOR) employed on site (SURVEYOR),
25 Managed (RAN-) the police department (Criminal Investigation Department = -CID) (RANCID) when one is off for a long time? (RANCID)
26 Statue (statue) destroyed (= anagram indicator) (statue = ASTUTE-) by port (port/left = -L-) yard (-Y) (ASTUTELY) in a cunning way (ASTUTELY),
27 Made fun of (TEASED) sedate (sedate) sort (= anagram indicator) (sedate = TEASED).
Down:
1 Food shop (DELI-) for cauliflower and cheese starters ('Cauliflower And Cheese' starters = -CAC-) to go with unknown quantity (-Y) (DELICACY) of frogs' legs, for instance (DELICACY),
2 Local mother (MA-) with eleven (-XI-) family members (-MUMS) (MAXIMUMS) producing the best possible results in snooker hall (MAXIMUMS),
3 Close to Jenner (close to ‘jenneR’ = R-) on Russian River (-URAL River) (RURAL) in the countryside (RURAL),
5 Type of swimmers charged for killing (ELECTRIC EELS) – it’s dramatic (ELECTRIC) for local, old scoundrels (heels) who lose the head (h) (‘heels’ without ‘h’ = EELS) (ELECTRIC EELS),
6 Spies (CIA = C-IA) hiding American (-A-) for time (-T-) briefly (e) isolated (alone) (‘alone’ without ‘e’ = -ALON-) (CATALONIA) in part of Spain (CATALONIA),
7 Do come off main road (‘do’ come off ‘main road’ = mainra = MARINA) for harbour (MARINA),
8 Struggle (RESIST) with weather? (RESIST),
11 What those in the abbey are doing (those in The Abbey Theatre / ACTING) employing teachers (SCHOOL) (ACTING SCHOOL) providing a series of lectures for those likely to play the fool (ACTING SCHOOL),
15 It appeals to a couple of beloved runners (ELOPEMENT) getting away for the match (ELOPEMENT),
16 Bankrolls (FINANCES) men preparing to join The Union (fiancés = FI-ANCES) around middle of the month (middle of ‘moNth’ = -N-) (FINANCES),
17 Popular (IN-) tenor (-T-) finished (-ENDED) (INTENDED) with fiancée (INTENDED),
19 It’s in the blood? (PLASMA) Raising (= reversal indicator) sheepish types (rams) off the summit (r) (‘rams’ without ‘r’ = ams = -SMA) on mountain! (alp = PLA-) (PLASMA),
20 Enthusiasm (SPIRIT) for email from imperialist (‘email’ from ‘imperialist’ = iprist = SPIRIT),
23 Neighbours (UK-) lose the head (c) with lawsuit (‘case’ without ‘c’ = -ASE) (UKASE) with Fiat? (fiat/formal decree = UKASE).