Across:
8 See leaving at leisure ('see' leaving 'at leisure' = atliur = RITUAL) for ceremony (RITUAL),
9 Dignity (GRAVITAS) in Irish love (Irish ‘love’ = ‘grá’ = GRA-) for strange (= anagram indicator) vista (vista = -VITAS) (GRAVITAS),
10 Recreates from treasure chest (‘recreates’ from ‘treasure chest’ = suht = SHUT) with seal (SHUT),
11 Odd (= anagram indicator) thing (thing = NIGHT) to convey (SHIFT) (NIGHT SHIFT) to those workers who spend their days in bed (NIGHT SHIFT),
12 Searching for information (ASKING) on the extremes of Anne of Cleves (on the extremes of ‘Anne of cleveS’ = AS-) and Henry VIII (-KING) (ASKING),
14 Short (k) opening (chink) (‘chink’ without ‘k’ = CHIN-) for Greek character (CHI-) getting to new (-N) (CHIN-CHIN) and to absent friends (to absent friends = a toast = CHIN-CHIN)
15 Exodus (DEPARTURE) – lie about (LOUNGE)? (DEPARTURE LOUNGE) where those taking flight rested? (DEPARTURE LOUNGE),
18 Model (= anagram indicator) is cross (is cross = SCISSOR-) with last boss (last ‘bosS’ = -S) (SCISSORS) employed by the barbers (SCISSORS),
20 Retiring (= reverse indicator) English (-E) soldier (Lieutenant = Lt = -TL-) associated with a crafty type (sub = BUS-) (BUSTLE) of activity (BUSTLE),
22 Bully (= anagram indicator) done paying (done paying = OPENING DAY) for the start of the season (OPENING DAY),
24 As well as (PLUS) blonde from Spellbound? (‘blonde’ from ‘spellbound’ = splu = PLUS),
25 Helped (ASSISTED) Bill (AD = A-D) accommodating self-starter (‘Self’ starter = -S-) briefly (r) employed in a hospital (sister) (‘sister’ without ‘r’ = -SISTE-) (ASSISTED),
26 Clip of (d) Rose (stood) (‘stood’ without ‘d’ = STOO-) sending up (= reverse indicator), for example (e.g. = -GE) (STOOGE), Patsy (STOOGE).
Down:
1 Opening 11 across (opening 'night shift' = NIGHT-) for society (-S) (NIGHTS) in Dark Times? (NIGHTS),
2 One of those with flawed pedigree (MUTT) starts to measure up to talent (starts/first letters of ‘Measure Up To Talent’ = MUTT),
3 Everyone (ALL) in 1 down (nights) contracted (s) (‘nights’ without ‘s’ = NIGHT) (ALL NIGHT) from dusk till dawn (ALL NIGHT),
4 Swallowed up (= reverse indicator) by Gallinago gallinago (‘swallowed up by ‘gallinaGO GAllinago’ = goga = AGOG) waiting with bated breath (AGOG),
5 Is able to (CAN-) get this (this) mostly (s) (‘this’ without ‘s’ = -THI) (CANTHI) from the corner of one’s eyes (CANTHI in the corner of eyes),
6 Places of entertainment (NIGHTCLUBS) in 1 down (nights = NIGHT-S) coming to grips with strike (-CLUB-) (NIGHTCLUBS),
7 What’s mystifying (BAFFLING) about (= reverse indicator) groovy (fab = BAF-) short love affair (-FLING)? (BAFFLING),
13 Acting (= anagram indicator) a bit insane (a bit insane = IN ABSENTIA) while away (IN ABSENTIA),
14 Creatures without true (‘creatures’ without ‘true’ = creas = CARES) worries (CARES),
16 Sam’s epic (Sam’s epic) adaptation (= anagram indicator) (Sam’s epic = ESCAPISM) appeals to those living the dream (ESCAPISM),
17 Bill’s pusher (pushing a legislative bill = LOBBYIST) in reception area (LOBBY-) is (-IS-) trouble from the start (‘Trouble’ from the start = -T) (LOBBYIST),
19 A tenor (a tenor) arrangement (= anagram indicator) (a tenor = ORNATE) is over-elaborate (ORNATE),
21 Slump (slump/laze = LOUNGE) from sudden movement (lunge = L-UNGE) welcoming oxygen (oxygen = -O-) (LOUNGE),
23 Concealed beyond a doubt (concealed ‘beyonD A DOubt’ = DADO) what divides upright types in The House (DADO rail divides uprights/walls),
24 Sporadically dismisses radical’s (‘sporadically’ dismisses ‘radicals’ = poly = PLOY) cunning plan (PLOY).