Across:
8 If the other crossword (Simplex) isn’t finished (x) (‘simplex’ without ‘x’ = SIMPLE) it’s not difficult to see why (SIMPLE),
9 Interpretation (EXEGESIS) of old love (EX-), for example (e.g. = -EG-), key (music key -E-) to what’s part of family life (sister = -SIS) (EXEGESIS),
10 Employer (USER) of cad getting out of used car (‘cad’ getting out of ‘used car’ = user = USER),
11 Art House (art house = SOUTH -REA) production (= anagram indicator) welcomes okay (OK) review (= reverse indicator) (OK = KO-) (SOUTH KOREA) from country in Asia (SOUTH KOREA),
12 Give out (ASSIGN) to fool (ASS-) upsetting soldier (GI = -IG-) in the middle of panic (middle of ‘paNic’ = -N) (ASSIGN),
14 Peacekeeper (UN-) with the German (the = -DER-) pup (-DOG) (UNDERDOG) one is likely to lose (UNDERDOG),
15 Most of those in 1 down (most of ‘firsts’ = FIRST) and 22 across (‘impression’ = IMPRESSION) (FIRST IMPRESSION) offering snap judgement that lasts a lifetime (FIRST IMPRESSION),
18 Supply (STOCK-) gin (gin = -ING) on the rocks (= anagram indicator) (STOCKING) popular during the Christmas season (Christmas STOCKING),
20 Comedian (GAS MAN) has a job reading things in other people’s homes (GASMAN),
22 What the mimic is capable of (IMPRESSION) or that’s the feeling? (IMPRESSION),
24 Stuff (PACK) in jam? (PACK),
25 Hard figures that won’t budge (STATUARY) for idols (idols/statues = STATUARY),
26 Cleared (ERASED) out of Red Sea (red sea) craft (= anagram indicator) (red sea = ERASED).
Down:
1 Irish men (Irish ‘men’ = FIR-) taking car (model -T-) in ship (-S-S) (FIRSTS) for unprecedented events (FIRSTS),
2 Fail to agree on (SPAR) spinning (= reverse indicator) music (rap = -PAR) by One Direction (South = S-) (SPAR),
3 He’s (HE-S-) left (-L-) inside writing material (-INK-) for institute (-I) (HELSINKI) in Europe (HELSINKI),
4 Romeo is one (BEAU) of the characters in The Globe audience (characters in ‘the gloBE AUdience’ = BEAU),
5 Form of play-acting (METHOD acting) by The Mod (the mod) movement (= anagram indicator) (the mod = METHOD),
6 It’s a delightful place (BED OF ROSES) presumably accommodating the women of Tralee? (the Roses of Tralee / BED OF ROSES),
7 Let’s get a move on (TIME TO GO), as this could be the witching hour (TIME) for West African country (Togo = TO GO) (TIME TO GO),
13 Lack of confidence (INSECURITY) provided by popular (IN-) refuge (-SECURITY) (INSECURITY),
14 A French (a = UN-) president (-P-), for example (e.g. = -EG) (UNPEG), let off the hook perhaps? (UNPEG),
16 Give someone an inkling of (allude to = INTIMATE) popular (IN-) short (p) bit of advice (‘tip’ without ‘p’ = -TI-) given to wife (-MATE) (INTIMATE),
17 One of those from The Cars (ENGINE-) and Queen (Elizabetha Regina = -ER) (ENGINEER) working in the sound studio (ENGINEER),
19 Put in place (INSTAL) by Stalin (Stalin) all over the place (= anagram indicator) (Stalin = INSTAL),
21 Reach (reach) out (= anagram indicator) (reach = ARCHE-) to head of recruitment (head of ‘Recruitment’ = -R) (ARCHER) having targets to hit (ARCHER),
23 Pass off displays (‘pass’ off ’displays’ = dily = IDYL) as a pastoral view of America (US spelling IDYL / idyll),
24 Lip reader dismisses idler (‘lip reader’ dismisses ‘idler’ = paer = PEAR) from the conference (conference PEAR).