Some excellent misdirection in the definition parts in this puzzle. Solving time, 22 mins.
* = anagram
ACROSS
1 CHEESY Double definition, Leicester being a type of cheese. Clue wording clearly pointing to a adjective.
4 S (CAFF)OLD
9 ACT(I)ON
10 MUENSTER (Tum’s ne’er)* A French cheese
11 STRATUM cf Stratus
13 TOP(P)ERS
14 CONTROVERSIAL (Into car lovers)* good misdirection with ‘vexed’
17 INCONTESTABLE (stable not nice)* ditto with ‘watertight’
20 ROAD MAP Cryptic definition way = r0ad
21 TAN GENT
23 PO I (TIER)S Battle in 100 Years’ War
24 M ‘IDDEN
25 DI’S PERSE(cuted)
26 BAR RE(a)L
DOWN
1 C (LASS AC)T
2 ENTER ON
3 SCO(U)T
5 COUNTER FE IT Good misdirection forge (vb)
6 FINE PRINT
7 OATMEAL (AA motel)*
8 D(U)RESS u = third letter of clubs
12 MOVING PARTS strap = (parts)*
15 RECOMBINE (one crime b)*
16 SENT INEL (line)*
17 ITALICS Cryptic definition
18 B(L)ENDER
19 TRIP O D
22 NAIRA Hidden reversal.