Across:
1 Satisfied (FULL) this has nothing (O-) to do with Furlong (-F) taking The Pledge (PROMISE) (FULL OF PROMISE) – potentially, it’s a sign of great things to come (FULL OF PROMISE),
10 A French (A = UN-) old hat (-DATED) (UNDATED) is of an era but not markedly so (UNDATED),
11 A (-A-) side of tuna (side of ‘Tuna’ = -T-) in sushi (sushi = SHI-SU) prepared (= anagram indicator) (SHIATSU) with Japanese pressure treatment (SHIATSU),
12 Some control a temper (some ‘controL A TEmper’ = LATE) – it’s long overdue (LATE),
13 It’s clear (PLAIN) novice (learner = -L-) is in agony (P-AIN) (PLAIN),
15 Put in the picture (TELL) on both sides of ten dollar bill (on both sides of ‘TEn dollar biLL’ = TELL),
17 Brought up (= reversal indicator) in Nazareth (in ‘NazAREth’ = are = ERA) during the time of Tiberius? (ERA),
19 It’s a dash in the car (dashboard in car = FASCIA board) for spies (-CIA) following (= positional indicator) Swift (fast) briefly (‘fast’ without ‘t’ = FAS-) (FASCIA),
21 Yours truly (MYSELF) holds back (= reversal indicator) most of the flesh (most of the ‘flesh’ = fles = -SELF) on heads of yellowish mangoes (heads of ‘Yellowish Mangoes’ = ym = MY-) (MYSELF),
22 Smokie’s (smokies = ESKIMOS) hit (= anagram indicator) with Kalaallisut speakers – great for breaking the ice presumably (ESKIMOS),
23 One in Trinity (one of “Father, Son, and Holy Spirit” = son) reviews (= reversal indicator) (son = NOS-) intros to Harvard University Press (intros to ‘Harvard University Press = -H-UP) (NOSH-UP) and makes a meal of it (NOSH-UP),
25 Where most peat is sourced (most of ‘bog’ = BO-) is where grapes are grown? (-VINE) (BOVINE) That’s a load of bull! (BOVINE),
27 Hiatus (GAP) in Singapore (in ‘sinGAPore’ = GAP),
29 Knock back (= reversal indicator) in Magnolia State (in ‘magnoLIA State’ = lias = SAIL) and leave the port (SAIL),
30 Idol’s (idols = SOLID) melody (= anagram indicator) is reliable, in a rocky way (reliable / rock SOLID),
31 Get lost (SHOO) in short (t) film (‘shoot’ without ‘t’ = SHOO),
34 One will have to move on (LET IT GO), as didn’t put a hand out for the bus (LET IT GO),
35 They’re not for the present time (FUTURES) or what’s to come (FUTURE-) at the end of Christmas (end of ‘christmaS’ = -S) (FUTURES),
36 Can’t get over the guilt (FULL OF REGRETS) of having no room (FULL) for (for = OF R-) flying (= anagram indicator) birds (-EGRETS) (FULL OF REGRETS).
Down:
2 Taped us (taped us = UPDATES) destroying (= anagram indicator) and breaking stories (UPDATES),
3 Old instrument (LUTE) reportedly (= homophone indicator) stolen by robbers (‘loot’ = ‘LUTE’),
4 Doctor (FIDDLE) and theologian (Doctor of Divinity = -DD-) mentioned in column (column/row = FI-LE) (FIDDLE),
5 Nod from dinosaurs (‘nod’ from ‘dinosaurs’ = isaurs = RUSSIA) in eastern Europe (RUSSIA),
6 Slung out of Mulligans – (‘slung’ out of ‘Mulligans’ = mlia = MAIL) what was the man of letters expecting? (MAIL),
7 Drinker (sot = SO T-) is present (-HERE) (SO THERE) – what are you going to do about it? (SO THERE),
8 Is this what happens when you go into your shell (FULL OF ONESELF) – you can’t take any more Pride? (FULL OF ONESELF),
9 On a guilt trip (FULL OF REMORSE), crammed (FULL) old French (Old French = OF) writing (from the 3Rs = R-) by key (music key -E-) pioneer on The Telegraph (-MORSE code via telegraph wire) (FULL OF REMORSE),
14 American (A-) resistance (-R-) to enemy (-RIVAL) (ARRIVAL) getting off Jumbo (ARRIVAL),
16 Eurosceptic dismisses soccer (‘Eurosceptic’ dismisses ‘soccer’ = eupti = TIE-UP) association (TIE-UP),
18 Heartless (heartless/remove centre = ‘a’) stable diet? (‘hay’ without ‘a’ = HY-) Offspring (-SON) (HYSON) to consume in China! (green China tea = HYSON),
20 Case in point – give up nicotine (‘case in point’ – give up ‘nicotine’/without ‘nicotine’ = asp = ASP), the poisonous type (ASP),
21 Master of Ballantrae opens (‘Master Of Ballantrae’ opens = MOB) in Ring? (ring/gang = MOB),
24 This (this = S-IH-T) revolves (= reverse indicator) around hospital (-H-) with mid-sized (mid ‘siZed’ = -Z-) unit opening (‘Unit’ opening = -U) (SHIH-TZU) for one type of dog (SHIH-TZU),
26 Receive (INHERIT) Vogue (IN-) and IT – her (it her = -HERIT) treat (= anagram indicator) (INHERIT),
27 Gang of heads (‘Gang Of’ heads = GO-) from The Dandy (toff = -T OFF) (GOT OFF) forgiven (GOT OFF),
28 Detective (PI-) is party (Fianna Fáil = -FF-) to the foreign (the = -LE) (PIFFLE) nonsense locally (PIFFLE),
32 Turn back (= reversal indicator), running behind (late = ET AL) the others in old Rome (ET AL),
33 Mix (STIR) of cast iron sample (‘caST IRon’ sample = STIR).