Across:
1 University (U-) post (-P-) associated with the Italian ('the' Italian = il) making a comeback (= reversal indicator) (il = -LI-) with paper (-FT) (UPLIFT) to inspire (UPLIFT)
4 They’re drawn (PICTURES) to 18 across from the start (start of ‘picture frame’ = PICTURE-) at school (-S) (PICTURES),
9 Worker (ant) falls over (= reversal indicator) (ant = -TNA-) in Cork (cap = CA-P) (CATNAP) – as a result of this, is unconscious briefly (CATNAP),
10 Ulster (U-) bus lane (bus lane) potentially (= anagram indicator) (bus lane = -NUSABLE) (UNUSABLE) is not fit for purpose (UNUSABLE),
12 Eagle, bear (eagle bear), bats (= anagram indicator) (eagle bear = AGREEABLE) in Nice? (nice = AGREEABLE),
13 Break loose avoiding laser (‘break loose’ avoiding/without ‘laser’ = bekoo = E-BOOK) – the one you can buy online (E-BOOK),
14 Opening 18 across (opening ‘picture frame’ = PICTURE) with 23 down (‘books’ = BOOKS) (PICTURE BOOKS) produced by graphic types that can’t be read (PICTURE BOOKS),
18 Imagine (imagine/visualise = PICTURE) 3 down (‘frame’ = FRAME) (PICTURE FRAME) holding up the Liffey Swim, for instance (PICTURE FRAME is holding up Jack B. Yeats’ “The Liffey Swim”),
21 Fiction (LIE-), for example (e.g.), upsets (= reversal indicator) (e.g. = -GE) (LIEGE) one of those in Belgium (LIEGE).
22 Clever people (wits) losing the head (w) (‘wits’ without ‘w’ = ITS-) with heartless (o) young man (boy) (‘boy’ without ‘o’ = by) falling over (= reverse indicator) (by = -Y B-) – it’s (-ITS-), yes (-Y) (ITSY-BITSY), of little substance! (ITSY-BITSY),
24 Update is (update is) signal (= anagram indicator) (update is = PUT ASIDE) to save for later (PUT ASIDE),
25 Without a care in the world (JOVIAL) for Smiley (JOVIAL),
26 Bar (bar/prohibit = PRECLUDE) in park (P-) is about (-RE-) to open for dinner (open for ‘Dinner’ = -D-) – it’s in guide that appeals to cruciverbalists (clue = -CLU-E) (PRECLUDE),
27 Area (A-) on top of seedy (top of ‘Seedy’ = -S-) place (-SET-) by small (-S) (ASSETS) estate? (ASSETS).
Down:
1 Opens up in a way (UNCLASPS) to tip from supplicants ('tip' from 'supplicants' = suplcans = UNCLASPS),
2 The ability to read the letters (LITERACY) from licence plate casing (‘LIcence plaTE’ casing = LITE-) on vehicle (car) going around (= reverse indicator) (car = -RAC-) yard (-Y) (LITERACY),
3 Engineer (FRAME) out of shape? (shape = FRAME),
5 Dropping off (IN NEED OF REST) Sleepy? (IN NEED OF REST),
6 It’s worth mentioning (TO SPEAK OF) to most of those from 8 down (most of ‘speaks’ = SPEAK) in a third of the yard (a third of a yard = foot)? On the contrary! (= reverse indicator) (foot = toof = TO OF) (TO SPEAK OF),
7 It’s concerning (RE-) to Wellington (Wellington -BOOT) (REBOOT), how one reacts to The Crash (REBOOT),
8 Gives an address (SPEAKS) in States (states = SPEAKS),
11 Dreaming (ABSENT-MINDED) of not being at work? (ABSENT-) Guard (-MIND-) and writer! (-ED) (ABSENT-MINDED),
15 Valise, urn (valise urn), box (= anagram indicator) (valise urn = UNIVERSAL) – applicable to all cases? (UNIVERSAL),
16 Section (PART -) from paper (Times) cut (s) (‘times’ without ‘s’= - TIME) (PART-TIME) by employee working on Weekend only perhaps (PART-TIME),
17 Tight (= anagram indicator) secrecy (secrecy = RECYC-ES) around port (port/left = -L-) (RECYCLES) plays into The Green’s agenda perhaps (RECYCLES),
19 Served up (= reverse indicator) friends (pals = SLAP-) at a wake (‘a wake’ = ‘awake’ = - UP) (SLAP-UP) a lavish meal (SLAP-UP),
20 Beat (beat) on the radio (= homophone indicator) (‘beat’ = ‘beet’ = BEET-) doing the rounds of Lake Tahoe (doing the rounds of ‘Lake tahoE’ = -LE) (BEETLE) produced by one of The Cars (BEETLE),
23 They’re bound (BOOKS) to be found in reserves (BOOKS).