I liked this a lot, with its very correct quotas of interesting vocabulary, artsy GK, and humorous constructions. COD to 12ac as the idea of a boatload of Father Christmases very much appealed. Thank you setter!
Done and dusted inside of 10 minutes; video evidence at
https://www.twitch.tv/videos/1476097154, from the 10 minute mark. Please excuse the increasingly wild and straggly beard, I’ve lost the power cord for my trimmer.
Definitions underlined in italics, (ABC)* indicating anagram of ABC, {} deletions and [] other indicators.
Across
1
Health ought not to be taken wholly for granted (8)
ALTHOUGH - {he}ALTH OUGH{t}, “not to be taken wholly”
5
Exercise in order to be cheerful? (4-2)
CHIN-UP - double def; if you tell someone “chin up!” you are ordering them to be cheerful
10
Going places, free at last? (5)
LOOSE - LOOS [places for “going”] + {fre}E, &lit
11
Post articles, including place for Creole dish (9)
JAMBALAYA - JAMB [post] + A and A “including” LAY [place]
12
Old naval commander’s spoken of Christmas holiday at sea? (5,4)
SANTA CRUZ - homophone of the delightful concept that is a SANTA CRUISE
13
Raffles maybe run once in newspaper, going back (5)
THIEF - HIE [run, once] in reversed FT. Raffles was E.W. Hornung’s gentlemanly literary cracksman.
14
Passage ancient poet largely avoided in recitation (7)
OVIDUCT - OVI{d} + homophone of DUCKED
16
A necessity to be originally called a dame (4-2)
NEED-BE - NEE [originally called] + DBE [Dame Commander]
19
Little plastic models (6)
SELDOM - (MODELS*)
21
Australian peach brandy factory employee? (7)
BOTTLER - a bottler is an excellent fellow, or suchlike, Down Under; and an important job in a brandy factory
23
More trouble as head’s dismissed (5)
OTHER - {b}OTHER
25
With cold, not on various drugs: drink from this (9)
COFFEEPOT - with C(old), OFF [not on] + E, E and POT
27
Conflict that was ended by The Sun (3,3,3)
SIX DAY WAR - began on Mon June 5, 1967, and was all over by the Sun (June 11).
28
Mammal’s four limbs it oddly passed over (5)
ORIBI - {f}O{u}R {l}I{m}B{s} I{t}
29
People moving, and people opposing, keeping bats caged (6)
NOMADS - NO’S [people opposing] “caging” MAD [bats]
30
For diversion, try C-list celebrity show (8)
STRICTLY - (TRY C-LIST*)
Down
1
Every American satellite passing over Pole, it’s implied (8)
ALLUSION - ALL U.S. IO [satellite of Jupiter] + N [pole]
2
Old player that you’d not want in your side finally vetoed by president (9)
THORNDIKE - THORN [that you’d not want in your side] + {vetoe}D + IKE. Sybil, with whom in mind for the title role George Bernard Shaw wrote Saint Joan.
3
East Ender perhaps who aspires to appear on a musical show (5)
OPERA - ‘OPER [Cockney unaspirated aspirant] on A
4
Asian state prison turning over an informer (7)
GUJARAT - reversed JUG + A RAT
6
Sign of life in bather swimming before lunch? (9)
HEARTBEAT - (BATHER*) before EAT
7
Outlet for soldier’s natural aggression, as fighting is, primarily (5)
NAAFI - N{atural} A{ggression} A{s} F{ighting} I{s}
8
Irrational: a very loud English Trot going nowhere! (6)
PIAFFE - PI: A FF E. On-the-spot dressage move
9
Long-distance runner to stagger after cutting leg (6)
AMAZON - AMAZ{e} + ON [leg]
15
Evidently give not enough away, being so secretive? (9)
UNDERHAND - if you under-hand out something, you don’t give enough away
17
Writer’s function and aim (9)
BALLPOINT - BALL [(social) function] + POINT [aim]
18
Yankee repairman quietly turning over deck (8)
PRETTIFY -Y FITTER P, all reversed
20
Parrots raising racket across wide area (6)
MACAWS - reversed SCAM “across” W A
21
Motion’s opponents won’t face rebuke (2,3,2)
BE FOR IT - and the opponents of a motion will be against, not “for” it
22
Continue to hoard old pennies and shillings for favoured child (6)
GODSON - GO ON, “hoarding” D S [as in LSD, pounds shillings pence]
24
Dickensian scavenger, he lifted as much as possible? (5)
HEXAM - HE + reversed MAX. Appears in Our Mutual Friend, right in chapter 1, messing about in boats on the Thames
26
Cause of complaint from lycée? Endless one (1,4)
E COLI - ÉCOL{e} + I