Across:
8 Surprise (Cor! = COR-) broadcast (-ON-) and article (-A) (CORONA) seen in The Sun? (CORONA),
9 A trooper (a trooper = OPERATOR) working (= anagram indicator) with engineer (OPERATOR),
10 No work for bookworm (no ‘work’ for/in ‘bookworm’ = boom = BOOM) to pick-up? (BOOM),
11 Set the table (DINE AT HOME) and briefly (m) lower the lights? (‘dim’ without ‘m’ = DI-) Well-ordered (neat = -NE AT) and that’s a sweet one! (HOME sweet home) (DINE AT HOME),
12 Compensate for the defects (REDEEM), as it is not in remedies? (‘is’ not in ‘remedies’ = remede = REDEEM),
14 Brief notes (MEM-OS) about ten (ten = -ENT-) lost (= anagram indicator) (MEMENTOS) souvenirs (MEMENTOS),
15 Storage facility (CLOUD) in Switzerland perhaps is for the birds (CUCKOO LAND) (CLOUD CUCKOO LAND) in a crazy sort of way (CLOUD CUCKOO LAND),
18 Sign (CLUE-) for takeaway (take away = -LESS) (CLUELESS) completely in the dark (CLUELESS),
20 Cleans up (TIDIES) with endless (p) horsey insider information (‘tip’ without ‘p’ = TI-) and stops working (-DIES) (TIDIES),
22 Don’t stand there if you want to keep your job (FIRING LINE) – the one with defined targets to hit (FIRING LINE),
24 Time (T-) to play the role (-ACT) (TACT) of foreign agent (TACT is of foreign agent/diplomat),
25 A preachy sort (MORALIST) of short encore (short encore/ ‘more’ = MOR-) to elite group of celebrities (A -list = -ALIST) (MORALIST),
26 Those in Sky (CLOUDS) opening 15 across (‘cloud cuckoo land’ = CLOUD-) on top of sports (top of ‘sports’ = -S) (CLOUDS).
Down:
1 Ill-humoured (MOROSE) beast (MO-OSE) swallows ram’s (rams) head (r) (‘rams’ head = -R-) (MOROSE),
2 Figure (FORM) tries to get away from firestorm (‘tries’ to get away from ‘firestorm’ = form = FORM),
3 Produced (= anagram indicator) denim cap (denim cap = PANDEMIC) that could be a killer if it goes global (PANDEMIC),
4 Selling out of wellingtons (‘selling’ out of ‘wellingtons’ = wton = TOWN) in urban area (TOWN),
5 Don’t panic (BE CALM) – it’s one of the problems trying to move the boat (no wind / BECALM),
6 Roughly treated (MANHANDLED) two workers (man + hand = MANHAND-) from the French (the = -LE-) Department (-D) (MANHANDLED),
7 Prosperous place (BOOMTOWN) with 10 across (BOOM-) and 4 down (-TOWN) (BOOMTOWN),
13 Turns up (= reversal indicator), popular (in = -NI-) bird (emu = -UME-) caught (-C-) in Chantilly, for example (Chantilly lace = EC-AL) (ECUMENICAL), is used to promote unity (ECUMENICAL),
14 Makes jokes about (MOCKS) the trials the students have to do before leaving (trials/tests before the Leaving Cert = MOCKS),
16 Lounge (lounge/laze = LOLL-) has one (-I-) soft drink (-POP) (LOLLIPOP) for local sucker (LOLLIPOP),
17 Teach our (teach our = OUTREACH) criminals (= anagram indicator) it’s available in the community programme (OUTREACH),
19 Photobomb (EDGE IN) a lot from delegation (‘a lot’ from ‘delegation’ = deegin = EDGE IN),
21 US co-ed (US co-ed = ESCUDO) travelling (= anagram indicator) to old European capital (capital/money = ESCUDO),
23 Very small (IOTA) item on the agenda, for starters (“item on the agenda” for starters/first letters = IOTA),
24 Consumed medication, for instance (TOOK), to (TO-) get all right (-OK) (TOOK).