Nice opener from Buzzer. Liked 8A, 11A & 3D.
ACROSS
ACROSS
8 Contents of diktat to opposition made lasting impression (6) TATTOO [T]
9 Helping a learner is sensible (8) RATIONAL {RATION}{A}{L}
10 Defence may perhaps close address early (8) REBUTTAL {RE}{BUT}{TALe} Not sure if Anno is correct (Correction - {RE}{BUT}{TALk} - See comments)
11 Issue brought up by one’s sister (6) NEPHEW [CD]
12, 19 One singularly incompetent sailor, old, to crash craft on shore soon after men went off (4,2,3,6,3,6,2,4) JACK OF ALL TRADES AND MASTER OF NONE {JACK} {O}{F ALL} {TRADE}{S AND} {MASTER OF NONE*}
14 Paroled criminal one spotted (7) LEOPARD*
16 Inspector took man for woman (7) DISTAFF {DI}{STAFF} Shouldn't that be 'women'?
19 See 12
22 Outstanding like Djokovic netting trophies endlessly (6) SUPERB {S{cUPs}ERB}
24 Business’ average for entertainer (8) COMEDIAN {CO}{MEDIAN}
25 Pronounced pressure on ship attendant (8) WAITRESS (~weight){WAIT}{RE}{SS} Not sure of anno See comments
26 Remove obstacle in river (6) DELETE {DE{LET}E}
DOWN
1 Best wishes to nurse … (4,4) TAKE CARE [DD]
2 … hit by small lorry (6) STRUCK {S}{TRUCK}
3 Design mascot for a family insignia (4,2,4) COAT OF ARMS*
4 Refrain from parts of central Alaska (3-2-2) TRA-LA-LA [T]
5 Put up whacky puzzle (4) STUN <=
6 Indoor growth which might yield grass? (3,5) POT PLANT [C&DD]
7 Cell door locked me in (6) GAMETE {GA{ME}TE}
13 Leotard I am wearing is perfect (6-4) TAILOR-MADE* &lit too
15 Good appearance given to capsicum (8) PIMIENTO {PI}{MIEN}{TO}
17 Punishment star suffered in creative pursuits (4,4) FINE ARTS {FINE} {STAR*}
18 Partners primarily booked over obscene acts sent across internet (7) WEBCAST {WE}{B}{ACTS*}
20 Pale, tense out of nerves (6) NEURAL NEUtRAL
21 Swelling number expected to welcome Labour leader (6) NODULE {NO}{DU{L}E}