Here’s my working
1 REHAB Should be here!
An &litish feel to this one, as you have to take the surface of the wordplay into account when working out where “here” is. EH corresponds to “what”, and a pub/bar backsliding gives you the containing RAB
4 FACETIOUS not serious
All the vowels in the right order. I like to stick an LY on the end to be absolutely sure. Tending to split is FACTIOUS, and the back of costume is E, to be enveloped.
9 CARPENTER Saw worker
Cutesy definition. Confined gives PENT, your embracing nurse is a CARER. Savour this little slice of life.
10 RATEL creature of the night
Be worth is RATE, and add a less florid version of £. Something I know about ratels: other than in South Africa, they’re honey badgers. Something I learned today: The Guiness Book of Records has it as the world’s most fearless creature.
11 SEDUCE divert.
A short pipe is a DUC(t)which you put through, ie into, SEE for spot.
12 AVIEMORE winter sports venue
Scotland’s finest (for all I know). Be extra competetive suggests VIE MORE. You need the A to put it “at”. Perhaps this (11/12) pairing suggests a government strategy for dealing with Scots Nats (see RECUSANT REALMS, below)
14 NATIONAL GRID power source
A well-flagged anagram of DRAINING A LOT.
17 SPEAKING TUBE Phone predecessor
A-level two cans and a piece of string. “In full flow” I think is just SPEAKING. I wanted it to be PEAKING but couldn’t find the S. Underground (in London anyway) is TUBE.
20 ECONOMIC cheap
A second “there you go, have an anagram” clue: ONE COMIC.
21 BIREME craft
Sounds like (to be picked up) buy ream. An ECONOMIC one presumably uses fewer rowers
23 LUNGI skirt.
Take the F(eminine) away from FLUNG and add 1(one). It’s a simple, unisex wrap around skirt, not unlike a sarong.
24 AS IT COMES in no particular way
A TV Programme is A SITCOM. Place two of the four points, E and S next door. Don’t think I’ve ever been invited to a LUNGI AS IT COMES party. Shame.
25 STATELESS being without a passport
I think I’ll leave this unexplained.
26 SYNOD meeting
A sound alike for SIN (wrong) and a reversd DO (party). Synods are ecclesiastical things: the idea of a STATELESS one is intriguing.
1 RECUSANT Stubbornly unorthodox.
A (ususally religious) dissenter from the prevailing discipline, probably an enthusiastic attender at the stateless synod. American US is dragged into RECANT. Another appealing surface presenting a little cameo. Salem? McCarthy?
2 HEREDITY …this
Another tidy &litish clue. HER/woman’s EDIT/alteration plus Y(ears)
3 BREACH OF PROMISE The Bardell case
Mr Pickwick, he of the Papers, was sued by the widow Mrs Martha Bardell for breaking off an engagement he didn’t know he’d proposed. You don’t need to know that if you put R(uns) into a sandy BEACH, and add a concoction of PROOF and SEMI, but, hey, why not read the book – it’s on Gutenberg. Another very decent surface.
4 FATE that one can’t avoid
Obese/FAT and E(nglish). From (I think) C19 Punch: Mary, the Irish maid, to her employer “Sor, what’s kismet?” “Why Mary, it’s fate”. Well in that case, me kismet’s killing me”. Antiquity is a defence against racial stereotyping.
5 CARAVAGGIO religious painting
Well, it says religious, but it was mostly an excuse to paint naked young men and boys, and violent executions that would be an inspiration to ISIS if they ever looked at that stuff. Was there ever a more obvious anagram that A VICAR AGOG? Fabulous art, by the way.
6 THREE RING CIRCUS Grand entertainment.
Yup, three rings at once, a forerunner of those busy CGI films where you never know quite where to look. Take two rings away from the Olympic five and make the rest up.
7 OPTION Possibility
Being taken to a new home could be seen as ADOPTION, lose the AD/notice
8 SOLDER join up
Take one (I) away from the private, who is one version of the SOLDIER.
13 PALATINATE Province
Not least in England during the times of feudal lords, and nothing to do with sultans and such. as I thought (if ever I did) before now. Head is PATE, place therein A LATIN European.
15 SUPERMAN hero
Tried to fit in some Greek until I realised it was DC. Or Nietzsche, I suppose. MA, your mother, “takes round” an anagram of PRUNES. Is OPTION SUPERMAN a section of Clark Kent’s wardrobe?
16 DECEASED Dead
Month is Dec, got milder EASED.
18 REALMS Areas
Significant is REAL, MS ManuScript writng. Ah, those Recusant Realms of the still technically United Kingdom.
19 GOANNA monitor
As in lizard. Apparently you Aussie types have trouble pronouncing iguana. GO ANNA! is the encouraging worplay.
22 BIAS partiality.
Half a prelate is a BIS(hop). Conceal A therein. Is “Caravaggio bias” a rather sophisticated way of suggesting one might gay?