All but two solved in 11 mins, 14 mins for those two making 25 mins in all.   7 across and 2 down which intersected - covered in notes below.   As always with Quixote, all fair, well-constructed and fully understood.     Practising what is preached in the Manual.

* = anagram
ACROSS
7 RIBOFLAVIN   One of my troublesome two, because I did not know the word   Rib of la(mb) “half cut” + vin (French wine - familiar and found in English dicts)
9  OBOE    OB = Old Boy  + one less n = note
11 ASTUTE  Needs a close cryptic look.  as = like + te = t(h)e “heartlessly”  “grasping”
i.e. holding TU leaders of trade union (first letters).  Would he have submitted this one
to the New Statesman?
14 TWITCH   Excellent surface.   The witch less the male (he)
15 LORD PRIVY SEAL  (lovers rapidly)*  Amusing surface.
18 DOPANT  Do + Pant
22 UNITES   E = English S = society  U = upper-class    nit = twit “initially” i.e. goes before es.  “Joins” is the definition

DOWN
2 ROGERS   The other of my troublesome two, in fact the more troublesome.  It’s (Ginger) Rogers, of musical and film fame, who I had heard of, but the difficult bit was “I understand” i.e. Roger which is what’s said when a radio message is received (and
understood).  I did know it, but took a while to work it out - a very satisfying final
solving moment.  s = son
5 TORTOISE  Another amusing surface    (Tories to)*
6 BOTTICELLI     Very famous artist  Beginning to booze = b    OTT = excessively    I repeatedly      Two Is holding cell i.e. exclusive party.   Another excellent surface.
16 REAL TIME  Hidden      ”more than adequate” means you need just some of the letters (in order of course)
17 PUT ASIDE  (a dispute)*
20 ARABLE “fit for cultivation”  Arab = horse on lea = meadow less a “not a”
24 RIOT    Threesome, first to last = trio (move the first letter to the end)

Time to ask Santa - I find the Franklin (pocket-sized) Crossword Solver very useful, take it with me all the time, trains, planes etc.  Main feature - key in ?s and known letters and it cycles through all the options e.g. ?l?e gives blue, glee, etc.  I use it, when away from dicts for verification (is there such a word? Are there alternatives?) or if stuck.    Vocab is v wide.  It has other features also e.g. anagram solver and synonym lists for common words, but it’s the ? I use most of all.

This has all I’ve learnt to expect from a Phi puzzle.    Perfectly worded clues, credible surface readings, variety, and a satisfied solver at the end.   I solved it in 15 mins.

* = anagram

1  PARKINSON’S LAW    “Work expands to fill the time available for its completion”.

Coined in the 1950s, with echoes of laws in physics re gases.   And, as anyone working in an office will tell you, many a true word is spoken in jest.   “Almost” stopping = parkin(g) with last letter off + (lass now)*

10  BOWDLER   Excellent surface.   Duck at outset = first letter d in bowler.   From the man who produced expurgated versions of the Shakespeare plays and the word’s gone into the language generally.

12  PLAY UP  lay in pup  Misleading because my first thought was a word meaning “bet”

13  DOOR  Do = party + OR (Other Ranks) - a crossword staple

18  RESILIENCE   RE (Royal Engineers - more soldiers familiar to solvers) + i in silence.

25 INDIANA   Indian = of Asian country  foremost in Asia = its first letter A.  Definition is State (of the US).

26 IRON MAN  New to me, this, apparently originated in Australia, series of sporting events, but the wordplay was straightforward.   What flattens = iron + man(y) = lots

27  NORTHALLERTON    In North Yorkshire.    (to holler ‘n’ rant)*    Hope some local worthies, not appreciating the cryptic crossword, do not see the clue.

DOWN

1  PENDULOUS    Tricky enough   pen = son (v well-known to solvers  - short for penitentiary) + dul(l) + ous(t) -  ”Nearly all reject”   The definition is the single word “hanging”

4  SUBS    Though main = sea is crossword cliche,  this was one of my favourites in the puzzle.     Subs meaning sub-editors and submarines in the two contexts.

5  NEW BLOOD    Double usage again here (the stage and the operating theatre).   Wondered though if this was close to breaking the normal convention of keeping serious diseases etc out of the grid.

8  STAGE DIRECTION  (Get actor inside)*   A wonderful &lit from the master i.e. the whole clue works as definition and wordplay.

15  DECEPTIVE  d = daughter + (r)eceptive   “Not right = r” 

16  ANCHORMAN   Another v good surface.    (monarch)* + an

17  SLAPDASH   PDA in Slash

24 PAUL   Paused with this, then saw it   U = university in China = mate = pal

A mixed bag. I found half the clues came very quickly, but there was a stubborn hard core, one of which eluded me to the end (but see comments for solution). Eight proper nouns, including real and fictional characters, including literary references not always kindly clued.

ACROSS:

1. COCKTAIL. A tail is a private eye, tip as in tip your hat, and Manhattan as in cocktail. Tricky subsidiary indications, but then what else could Manhattan be?

5. ONEGIN. (gone)* + IN. Again, I can’t think of any other Eugenes, so unless he’s the anagram…

10. Open to offers. I’ve got CRONIN, but don’t see where the samurai fits.

11. I’m stumped. Thought initially it was a not v cryptic clue for marathon. The runner looks like a plant to me. I can’t get Stratford or Hackney marshes in there anywhere. (See below).

18. ALLOTROPIC. A pair of lines = A L L, circle = O, imaginary line= TROPIC.

22. HYSSOP is hidden. But how does ‘about’ indicate that?

24. ARAMIS. Ar + Amis. One of the Three Musketeers.

26. HORNET. (thorne)*.

DOWN:

1. CALLAS. Hidden + lit.

2. CARMAN. Ref George Carman QC and Harriet Harman - very difficult, esp without telling you what replaces the politician’s head.

3. I had TAIWAN, but couldn’t explain it - now I see it’s TAIPAN, with P of pine replacing W for wife. Must mean a foreign businessman in China.

13, OCCIDENTAL. (col acted in)*. Who’s Col? Could the anagram be any clearer?

15. MACHEATH. Informal adress = Mac, former PM = Heath. I associate Macheath with Brecht’s Threepenny opera, but he began life in John Gay’s Beggar’s Opera.

17. ATROPINE. (A protein)*. Nice anag.

20. CASTLE. L(ambert) in CASTE - Lambert being a measurement of…?

21. PENNON. PEN N ON. Note can be any of letters A-G, or Do-Mi - or N. So just about anything, really!