Fifteensquared

Much like 1A, this puzzle had a solid enough core but lacked that extra flair and creativity to put it in the running for any major accolades.

Across
1 LIVERPOOL - (role old VIP)*- d[irector].
6 ASHEN - as hen.
9 PILOT - I[taly] in plot.
10 FROSTBITE - re: the nasal, Keyhole-throughgoer, (Sir) David Frost.
11 REAR WINDOW – (reward I won)*.  Fortunately, my superficial knowledge of Hitchcock’s work (i.e. the film titles only) always seems to be sufficient for crossword purposes.
12 JAZZ - J[oint] + a + zz.
14 ASININE - sin in {M}aine.
15 TRAFFIC - a f[ine] f[ellow] in tric{e}.
17 COYNESS - y[ard] in Co. + ness.
19 CAT’S-EYE - (as yet)* in C{heshir}e.  Brainchild of Percy Shaw- professional Yorkshireman and endearing eccentric.
20 IOTA - I + {r}ota.
22 MONTENEGRO - (ten + e.g. + r[ule]) in Mono.
25 ENDEAVOUR - Cap’n Cook’s antipodean vessel.  Good to see an Endeavour clue that doesn’t resort to Morse…
26 MAIZE - homophone of “maze”.
27 TERSE - hidden.
28 FORESIGHT - homophone of “for site”.

Down
1 LEPER - p{olice} in leer.
2 VULGARITY – v + (guy trial)*.
3 ROTTWEILER - (letter in row)* – n.
4 OFFENCE - of fence{r}.
5 LOOK-OUT - double def’n.
6 ARTY - hidden.
7 HAIFA - initial letters.
8 NIETZSCHE - {metap}h{ysics} in (cites Zen)*.
13 MARTIN AMIS - A.M. in martinis.  By some bizarre bolt of inspiration, I instantly and inexlicably thought of the answer purely on the basis of the word “writer” and the enumeration.  The niftily concise wordplay tookk a little longer to fathom.
16 FLEDGLING - Fl + (l in edging).
18 SHOW-OFF- double def’n.
19 CATERER- te in carer.
21 TUDOR – {S}troud*.
23 OVERT - over + t{hrill}.
24 CAVE- double def’n.