Times Cryptic 26342

I found this one quite tricky and needed a little over an hour to complete it.

As usual deletions are in curly brackets and indicators in square ones.

Across
1	PROOF – PRO (master), OF
4	MACERATE – MACE (official staff), RATE (charge)
8	ELDER STATESMAN – ELDER (presbyter), STATES (announces), MAN (staff)
10	HARMONICA – Anagram [poor] of CHAIR{w}OMAN [cut With]
11	SKEIN – SKIN (hide) around {cops}E [back]. Def: flock on the move. This came up in Dean’s most recent ST puzzle and was discussed here only last week.
12	LOBATE – O{f} + B{arley} [primarily] inside LATE (behind time). Not sure I actually knew this word but it didn’t take much working out.
14	PERCEIVE – Anagram [playing] of PIECE + {e}VER{y} [heart of]
17	GROUNDED – {bein}G [close], ROUNDED (plump)
18	SEA DOG – SEA (main), DOG (trouble)
20	SHEAF – EH (what) inside FAS (notes) all reversed
22	RETICULAR – RE (engineers), {par}TICULAR (attentive to detail) [removing part]. I wondered if RET could  be engineers which would have allowed us to remove all four letters of ‘part’ from the longer word, but I think it’s just the usual sappers and the T remains in place.
24	OVERCOMPENSATE – OVER (past), CO (company), then MPS (members) enclosing E{nglishma}N [case], ATE (worried)
25	INTERNEE – INTER (put under – bury), NEE{d} (obligation) [briefly]
26	SWEPT – {n}EWS (info) [dropping first] reversed [back], PT (part)
Down
1	PSEPHOLOGIST – Anagram [dreadful] of GOSSIP TO HELP. I struggled with this one although it’s a word I have known all my adult life. I would have expected a reference to elections or voting patterns in the definition which appears to be ‘dedicated social scientist’. I suppose ‘dedicated’ suggests that we’re looking for a specific branch of social science but we’re given no indication as to what area that might be.
2	ORDER – Triple definition
3	FORGOTTEN – FOR{d} (ex-president) [briefly], GOTTEN (arrested in US) which also came up very recently and caused some discussion. I can’t quite square it with ‘arrested’ in any of the usual sources but perhaps one of our US correspondents would care to confirm the usage?
4	MATRIX – Sounds like ‘May’ (springtime), ‘tricks’ (is deceptive)
5	COTTAGER – CO (commander), REGATT{a} (meeting on river) [short]. ‘Rural labourer’ is the nearest I can find to ‘countryman’. I don’t think regattas are exclusively river events.
6	RASPS – S (society) inside SPAR (box) reversed [mounting]
7	TRADEWIND – TRADE (business), WIND (blow)
9	UNDERGARMENT – Anagram [out] of GERMAN TURNED
13	BROKE EVEN – B[L->R]OKE (chap) [changing sides – L/R], EVEN (still)
15	CRESCENTS – C{a}R{t}E{l} [every so often], SCENTS (picks up). I like the definition ‘bent ways’.
16	BEAR DOWN – BEARD (Vandyke, say), OWN (particular)
19	STAPLE – STA[B->P]LE (firm/basic). B (British) changes to P (pressure)
21	FURZE – Sounds like [we’re told] “furs” (unethical form of covering). But not unethical if worn by the original owners!
23	LEAVE – LEAVE{s} (pages) [most of]