Some pleasing material here from this inventive setter.

Solving time:  25 mins

* = anagram

ACROSS

1 COAT OF ARMS    (A from Ascot)*    Did not see this till late on. “becomes” indicates the anagram.

6 BA (R EX) A M(ida)S    Baa = lamb’s remark!

10 FERRYMAN   Cryptic definition that I got first time around.

11 STATE OF PLAY    Shakepeare’s play, Hamlet, is set in Denmark.

23 GREECE   “Grease” 1970s musical set in the 1950s.     Had never heard of bouzouki, so looked it up.  It’s in the Concise OED as a mandolin played in Greece, so got the answer then.

24 Marlene DIET RICH

25 B (EAT) IT    I think.     Seems to fit wordplay, but definition = get, apparently, I’m not too sure about.

DOWN

1 B OUNCE   Stock market term dead cat bounce.

2 WA(l)TER Mitty LEVEL

3 P (EER GYN) T  (energy)* in pt = part.     release indicates the anagram - I was looking for a long time for e = energy leaving something.    This was only to check though because the answer I was familiar with.

5 ALPHABET  “Stored in it all the letters one writes?”     A magnificent cryptic defintion, with misleading context of a drawer or bureau.

16 NOR THE  RN   Line in the US, South of which lay the slave states and North the others.

19 SCREE N = Newton (unit of force - physics).     Was looking for an anagram of Newton until I’d a confirmed crossing letter not among those six.

20 ABE D   Remember Abe Lincoln

21 TUBE (r)

A pretty straightforward Monday solve (10 mins-ish), tightly clued and accessible as ever, with quite a few anagrams and lots of cryptic definitions - some very good, others a tad obvious. About half the answers came more or less straight away, but there was some tougher meat in there too, with 9 across detaining me for a little while.

ACROSS:

9. MAN OEUVRE. The last piece of the puzzle for me. I had MAN for ‘work on’, and was looking for a _E_V_E island to complete it, but of course cruciverbal man is an island. 

10. A BEAM. In the very simple category.

12. PLAN ETS (SET*). Luckily about as far as my knowledge of Holst’s oeuvre goes.

14. GERMINATE. (A REGIMENT*). Nicely phrased anagram, with misleading surface.

16. NON-PROFESSIONAL. (LOAN FOR PENSIONS). My favourite - non-0bvious  definition and anagrind, with only six letters in addition to the anagram fodder.

19. SUMP TU OUS (SOU*). Another relatively hard one - ‘well’ doesn’t immediately shout ’sump’ tp me, and I didn’t immediately spot that it was ‘you’ that needed Frenchifying. One quibble - the clue led me to expect an anagram of ‘A SOU’, not just ‘SOU’.

24. OPERA. Ref ’soap opera’… and while opera=works is not general usage, we see it every time a setter uses ‘op’ for work. Singular opus, plural opera.

25. FAST TRAIN. CD, pun on fasting, which we saw within the last month or so elsewhere in our blog domain, in a clue for ‘dining-car’. Can’t remember whose.

DOWN:

1. AMUSEMENTS. (SEAMEN MUST*). Another good tight anagram.

2. ON THE RUN. (NO HUNTER). Nice anagram, with weak indicator - ‘but possibly’.

5. KEY PHRASES. Another nice punning CD.

6. HARA-KIRI. ‘Self-effacing’ in the literal sense of obliterating oneself.

14. GIFT OF LIFE. CD, but ‘living’ for life is not ideal.

15. ENLIGH(TEN)S. Good clue. I was looking for E+(composition) - but it’s another anag.

17. RAT IONA L. NIce use of ‘desert island’.

20. MAY HEM. I don’t think ‘mayhem’ is necessarily a criminal act, but I believe it had that sense historically. Certainly it can be bordering on one, but that means borrowing a bit of the wordplay.

22. PLOT. means plan, but does it also mean parking place, or is it P+LOT - in which case why does ‘place’ mean ‘lot’?