Solving time: 21 mins. Held up for some time by thinking a very well-known actress had a U in her name though there was none in the anagram fodder (6 across).
In line with recent practice, will comment on just a few of what seemed to me the trickier clues, but happy to explain any others if asked.
< = reversed
ACROSS
8 BRUISE “Brews”
10 PIT I (LES) S Definition = stony ditch = pit
16 OB (Old Boy = former pupil) LATE et al <
DOWN
2 FLEECE Double definition
4 W (OR = Other ranks = soldiers M = beginning to move (first letter) ) HOLE
21 PU (up< “ascending”) FF (ff very loudly – music)