ACROSS
 8. H (ALFRED PENNYWORTH) - RED = HALFPENNYWORTH <advice>
10. RE + MORSE = REMORSE <grief>
11. <design> ART DECO = RATED* + CO
12. S ALES = SALES <discounts>
14. <sneaky> DISHONEST = DISH ON SET*
16. <cricket club> NO TT + [-g]INGHAMS HIRE
18. <the King was associated with this> ROCK 'N' ROLL = ROC (N inside KNOLL)
20. <make fresh> RENEW = ←WIENER← - _I
22. ←MO'S← A TIC = SOMATIC <in the body>
24. TARIFF* C = TRAFFIC <trade>
26. <mob activity> ORGANISED CRIME = OR GRIME outside ANISE DC

DOWN
 1+16d+9+21. <saw> THERE'S NO REST FOR THE WICKED = THE RE SNORES T_ (_H inside FORTE) WICKED
 2. <type of rock> GLAM = _L_ inside GAM
 3. OP + PRESS + _I_ ON = OPPRESSION <despotism>
 4. UNDERDOING - IN = UNDERDOG <sympathetic contestant>
 5. <avoid> BYPASS = BASS outside Y_P
 6. BOA T = BOAT <vehicle>
 7. <islander> ST HELENIAN = S THE (A inside LENIN)
13. <fashionable partygoers, perhaps> LATECOMERS = (MALE ESCORT)*
15. (BANS CORVEE)* = OBSERVANCE <custom>
17. <excited> = AFL UTTER
19. OR (HID after _C) = ORCHID <plant>
23. TEA T = TEAT <drink supplier>
25. F AIL = FAIL <not succeed>