Across
1 It was a charmless Christmas (‘Christmas’ without ‘charm’ = -ISTS) for Josephine, in short (JO-), but she’ll get some support from these (get some support from these = JOISTS).
4 In the middle of the inspection (-SPEC-) the promissory notes (IOUS) were found to be utterly implausible (=SPECIOUS).
9 Is all lost (Is all lost = remove ‘IS ALL’) from the Emerald Isle (=EMERALD ISLE) (EMERALD ISLE - ALL IS = EMERDE) or could this restore our honour (=REDEEM)?
10 He fills his estate (He fills his estate = ‘HE’ in ‘ESTATE’) with beautiful things! (= AESTHETE)
12 Begs (=BESEECHES) for Edam and Gouda, perhaps (=CHEESES), around (indicates anagram) Belgium (=BE).
13 A strong leader (=S) and hearty too (‘and hearty too’ ref. ‘HALE and hearty’), perhaps, with many layers (=SHALE).
14 Around the capital of Latvia (‘Around the capital of Latvia’ = anagram of RIGA), what relates to artistic or intellectual endeavour (=CULTURAL) is a growth business (=AGRICULTURAL).
18 You might need 1, 21 and 25 across (‘joists’, ‘slate’ and ‘rafter’) to do this (literally, RAISE THE ROOF) with exuberance (= RAISE THE ROOF).
21 He postulates about the spout when they just need to get on with laying (i.e. laying SLATE) what’s left (Remove SPOUT from POSTULATES to get ‘what’s left’ = SLATE).
22 A petty formality, perhaps (= PUNCTILIO), to fudge (‘fudge’ = anagram indicator) the topic until (= TOPIC UNTIL) tea (T) is taken (‘is taken’ = remove letter) (OPICUNTIL = PUNCTILIO).
24 It’s spread (= EPIDEMIC) about (indicates anagram) that mice (= MICE) took a swim (‘swim’ = DIP) back (= reverse indicator, DIP = PID) east (= E).
25 Right, first (‘Right, first’ = R) attach this, but not before (‘not before’ = AFTER) 1 across (‘joist’), for additional support (= RAFTER).
26 As odd (ref. ‘strange’) a person as you’ll ever meet! (= STRANGER)
27 Don’t do this. Keep your promise (i.e. ‘don’t keep your promise’ = RENEGE) and you’ll secure a pact from a percentage (remove ‘pact’ from ‘percentage’ = ERENGE) of them at least.
Down
1 You might 18 across (‘raise the roof’) having one of these to celebrate (JEROBOAM) getting a job in Rome (a job in Rome = AJOBROME i.e. letters of JEROBOAM).
2 In the beginning (=IN), what’s at the heart of this (DUST) is what we have always been (ref. ‘dust to dust’), really, from start to finish (really, from start to finish = RY), despite all of this busy work (busy work = INDUSTRY).
3 Have no fear hereafter (no ‘fear’ in ‘hereafter’ = HETER) in that place (=THERE).
5 Push for (= PRESS) editing (= CUTTING) the magazine piece (=PRESS CUTTING)
6 A small country (=CITY STATE) that is teetotal (TT) around the (around the = anagram indicator) icy East (ICY EAST). (TTICYEAST = CITY STATE)
7 There’s no turning back! (Literally ‘ONE-WAY’)
8 The reek (REEK) around (‘around’=anagram indicator) the west (W) and south (S) would go through you (would go through you = SKEWER).
11 Open your mind (= PHILOSOPHISE) and arrange (=anagram indicator) short vacations (=HOLS) for flower-children (HIPPIES) at the start of October (= O). (HOLSHIPPIESO = PHILOSOPHISE)
15 Changeable fellow (= CHAMELEON) with unusually (unusually = anagram indicator) clean home (CLEANHOME = CHAMELEON).
16 Might a trout and eel go round (‘trout and eel go round’ = anagram of TROUT and EEL) and round like this? (‘go round and round like this’ = ROULETTE)
17 Certainly (= OF COURSE) not going in the right direction (= ‘off course’), by the sound of it (= homophone indicator, ‘off course’ sounds like OF COURSE).
19 It’s good to own (= ASSETS) what one consumes (=EATS) with the secret service (=SS).
20 So sharp (= RAPIER) it could rip (= RIP) your ear (= EAR) off. (off = anagram indicator)
23 When the moderator leaves the room (= remove ‘room’ from ‘moderator’ = DEATR), arrange (= anagram indicator) to seal the deal (= TRADE).