Across
Bearing thanks, King George departed to tour Thailand (8)
I haven't cracked this one yet — but Fifteensquared have:
[gr]ATITUDE (thanks) minus GR (Georgius Rex – King George) round T (Thailand)
Be no longer in the lead? (5)
Support the other side (4)
One day in seven I'll eradicate ragwort, primarily with this? (10)
I haven't cracked this one yet — but Fifteensquared have:
D (one day) in WEEK (seven days) + I’LL + E[radicate] R[agwort]
Determined supporter boring Sylvester Stallone (6)
Gary isn't cast in 1960s' TV series (8)
E-lation? (7)
I haven't cracked this one yet — but Fifteensquared have:
I need help here: it must be a double definition but I can’t see how to express it.
Drunk pinches copper and metal (7)
A British party is caught after doing a U-turn, sharp (8)
I haven't cracked this one yet — but Fifteensquared have:
A B (British) + RAVE (party) round a reversal (after doing a U-turn) of IS
Sturgeon's playing a bugle (6)
Everton gutted — thumps in dodgy penalty (10)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (dodgy) of E[verto]N THUMPS IN – great surface
Leaders of Newcastle usually taunt Sunderland fans (4)
Swimmers swim on vacation, including exercise by river (5)
I haven't cracked this one yet — but Fifteensquared have:
S[wi]M round PE (exercise) + R (river)
Everybody loves a posh royal, one who's an old predator? (8)
I haven't cracked this one yet — but Fifteensquared have:
ALL (everybody) + OS (loves) + A + U (posh) + R (royal)
Down
Local network installed in loft by the ocean (8)
10(1000000)00? It's a beast (4)
I haven't cracked this one yet — but Fifteensquared have:
M (1,000,000) IN K (1,000) – I love Qaos’ ‘mathematical’ clues!
Move around the Tube, essentially underground in America (6)
I serve differently to conclude Federer's final game (7)
I haven't cracked this one yet — but Fifteensquared have:
An anagram (differently) of I SERVE + federeR – I can’t see why we need both ‘conclude’ and ‘final’ Here’s the game
Bill's old schoolmaster (4)
Every other Briton's reasonable and related by blood (10)
I haven't cracked this one yet — but Fifteensquared have:
Alternate letters of BrItOn + LOGICAL (reasonable)
In Judea, the nativity reveals deity (6)
Delivers suspect walk-on part? I'd stumble over scenery (10)
I haven't cracked this one yet — but Fifteensquared have:
I’m not quite sure how this fits together: EXTRA (walk-on part) + a reversal (stumble over) of SET (scenery) I’D – or is it an anagram (stumble) of I’D + a reversal (over) of SET (scenery)?
Announcement: 50% off diamonds! (3)
Runner is climbing over the summit of Kilimanjaro (3)
I haven't cracked this one yet — but Fifteensquared have:
A reversal (climbing, in a down clue) of IS round K[ilimanjaro]
Just terrible losing crown (8)
Common soldier (7)
Having no immediate use, king leaves in musical style (6)
I haven't cracked this one yet — but Fifteensquared have:
BLUE S[k]Y (having no immediate use) minus k (king)
Adult abandons fight over oxygen container (6)
I haven't cracked this one yet — but Fifteensquared have:
B[a]TTLE (fight) minus a (adult) round O (oxygen)
Opening of honeypot? I'm not sure — tip from Pooh Bear (4)
I haven't cracked this one yet — but Fifteensquared have:
H[oneypot] + UM (I’m not sure) + P[ooh] – a neat lift and separate: bear = carry
Feature of numbers with natural base (4)
Type letters or click words in the clue