As usual, an excellent puzzle from the ever-reliable Phi. Solving time, 21 mins.
* = anagram < = reversed
ACROSS
1 (PIPPED) (AT THE POST) Tempted at first by the 15 letters after ’stoned’ which suggested an anagram.
9 L ((r)A SCAL) A
10 P (ROT E.G). E
11 COO (l)
12 A U CONTR (AIR) E (counter)*
13 COR ROSION (so iron)*
15 P (AYE) E Complicated. A couple of pence = PEnce AYE = certainly. On the contrary = rather than put PE inside AYE, do the opposite.
16 Thomas N ASHE(s) from the late 1500s
18 TRUCELESS (ulcers set)*
20 TREAC (HERO) US (act sure)* Join at deceitful/act was cleverly misleading.
22 GYM Cryptic definition (More to it than this, thanks, Rayfolwell for comment 2 below)
23 B (ALAN) CE BCE = Before the Common Era, same as BC
24 A MATE (yoU) R Tip-top surface
25 ESCHERICHIA COLI (choice chilis are)* Better known as E COLI
DOWN
1 POL (lop<) ICE CONS TABLE
2 P IS SOIR (evening in French)
3 ERA Hidden Another good join period/furniture
4 AN (ARCH IS) T
5 TA P-IN
6 E GO TRIPPERS
7 OBE (SIT) Y
8 THE S (EVEN S) AMURAI (amateurish)* nmsindy is normally weak on films, but, not only knows this one but saw it around 1960, I think.
12 A DOLE SCEN (C) E
14 NEUROPATH (upon earth)*
17 S (HELL) AC
19 EL G(a)R Exciting CO
21 ELEMI hidden< Ain’t seen this word, so familiar in crosswords, for quite a while now.
25 ADA I think this appears in datA DAta i.e. repeatedly