Very entertaining to both solve and blog. Thank you Serpent.

ACROSS | ||
1 | AMICABLE | Good-natured question politician once asked himself (8) |
AM I CABLE is a question that Vince Cable (former politician) might have asked himself | ||
6 | SODA | Drink when drinking party returns (4) |
AS (when) contains (drinking) DO (party) reversed (returns) | ||
9 | VEIN | Reporter’s egotistical passage that’s essential for circulation (4) |
sounds like (reporter’s) “vain” (egotistical) | ||
10 | BALDERDASH | Style having fewer frills could be rubbish (10) |
cryptically a BALDER DASH would be dash (style) that is balder (having fewer frills) | ||
11 | UNTIDIER | More disorderly reforms united leaders of Irish Republic (8) |
anagram (reforms) UNITED with first letters (leaders) of Irish Republic | ||
12 | CANDID | Outspoken French satire without the letter ‘e’ (6) |
CANDIDe (satiric novel by Voltaire) missing the letter E | ||
13 | MADAM | She accommodates solicitors either way (5) |
cryptic definition and palindrome – a keeper of a house of ill-repute | ||
14 | NOISELESS | Is Head of Eton stopping lesson being broadcast still? (9) |
anagram (being broadcast) of IS with Eton (first letter, head of) and LESSON | ||
18 | RECTITUDE | Integrity of conviction leads to criminal record being overturned (9) |
CERTITUDE (conviction) with the first letters (leads) to Criminal and Record being swapped (overturned) | ||
20 | USURY | What generates much interest as a rule needs everything to be right (5) |
USUALLY (as a rule) with ALL (everything) becoming R (right) | ||
23 | OPTION | Travelling into work introduces an alternative (6) |
anagram (travelling) of INTO follows (that…introduces) OP (work) | ||
25 | NEWSCAST | Show four people holding hands with actors (8) |
NEWS (North, East, West and South, four people holding hands of cards) with CAST (actors) | ||
26 | CONTRADICT | Disagree with senior policeman blocking agreement (10) |
DI (Detective Inspector, senior policeman) inside (blocking) CONTRACT (agreement) | ||
27 | UGLY | Snug Lycra trousers lacking appealing features (4) |
found inside (trousered by, pocketed) snUG LYcra | ||
28 | STIR | Legal documents about axing women’s prison (4) |
wRITS (legal documents) reversed (about) missing W (women) | ||
29 | DOGGEREL | Bull gored leg badly (8) |
anagram (badly) of GORED LEG | ||
DOWN | ||
2 | MENDICANT | Doctor obtaining new social worker for charity case (9) |
MEDIC (doctor) contains (obtaining) N (new) then ANT (social worker) | ||
3 | CABBIE | BBC matinee regularly broadcast Taxi Driver (6) |
anagram (broadcast) of BBC and mAtInE (taken regularly) | ||
4 | BALLROOM DANCING | Opportunity grasped by heartless lad in evening up for social whirl? (8,7) |
ROOM (opportunity) inside (grasped by) LaD (heartless) all inside BALANCING (evening up) | ||
5 | EXERCISE | Work out tax cut with head of state (8) |
EXCISE (tax) contains (cut with) ER (Elizabeth Regina, the head of state) | ||
6 | SEDAN | Witnessed animal bearing litter (5) |
found inside (… is bearing) witnesSED ANimal | ||
7 | DISMISS | Refuse to consider statement of Norfolk woman (7) |
sounds like (statement of) “Diss miss” (a woman from the town of Diss in Norfolk) | ||
8 | HERNIA | Medical condition affected hearing mostly (6) |
anagram (affected) of HEARINg (mostly) | ||
13/16 | MARSHY | Start replacing second half of trading area like Slough (6) |
MARket (trading area) with second half being replaced with SHY (start, take alarm) | ||
15 | LOST CAUSE | Spooner’s interpretation of penalty regulations in hopeless case (4,5) |
a Spoonerism of “cost laws” (penalty regulations) | ||
16 | See 13 | |
17 | STANDARD | Average level of quality that may be raised (8) |
double or perhaps triple definition | ||
19 | EXPLOIT | Plan no longer includes current use (7) |
EX-PLOT (a plan, no longer) contains I (current, electrical symbol) | ||
21 | RUSTLE | Take stock of regulation covering terms of onerous contract (6) |
RULE (regulation) contains (covering) last letters (terms, ends) of onerouS contracT – stock might be cattle | ||
22 | SWATHE | Cover up man supporting strike action (6) |
HE (man) underneath (supporting) SWAT (an action of striking) | ||
24 | INTER | Football team‘s place in ground (5) |
double definition – Inter Milan |