This Cincinnus puzzle struck me as distinctly more difficult than most of his. The top-right corner especially took me some time to complete. And it has its complement of splendid Cincinnic clues (10A, 25A, 3D).
Across
1. BEAGLE – double definition. This clue seems hardly cryptic.
4. SCHOONER – CH (central heating) in SOONER (preferably)
9. BUCKS – double definition
10. LUMBERING – double/cryptic definition
11. LIE DOWN – LIED (having misrepresented the facts) + OWN (confess)
12. AUSTERE – AUSTER (south wind) + E (energy)
13. NAIL – double definition
14. SEDIMENT – cryptic definition
17. NAVARINO (see comment 1 below)
19. STIR – double definition
22. REPINED – RE (about) + PINE (long) + D (note)
24. ARC LAMP – A (a) + [pape]R + CLAMP (binder)
25. CARL LEWIS – anagram of RACES WILL
26. AGREE – hidden word
27. REHEARSE – [st]RE[et] + HEARSE (vehicle for last journey)
28. BLIMEY – B (initially Brit) + LIMEY (Brit)
Down
1. BOBOLINK – BOB (Robert) + O[ppenheimer] + LINK (associate)
2. ACCRETION – anagram of TO CAR NICE
3. LISTON – L (50) + IS (=) + TON (100)
5. COMPANIONWAYS – COMPANION (fellow) + WAYS (means to provide)
6. OVERSEE – VERSE (poetry) in OE (Old English)
7. NOISE – hidden word
8. ROGUES – anagram of GROUSE
10. LONGEARED OWLS – anagram of DO LEGAL OWNERS
15. TETRAGRAM – T[rooper] in MARGARET (princess) backwards
16. FRIPPERY – RIPPER (Jack who was killing) in F[unn]Y
18. VANILLA – AN (article) in VILLA (house)
20. GROCER – homophone (“grosser”)
21. SCRAWL – S[ubeditor] + CRAWL (make slow progress)
23. PERCH – double definition
17a NAVARINO – ON IRA (terrorist) VAN (front) reversed – the naval battle fought in 1827 during the Greek War of Independence.
I think ‘terrorist’ should have been either plural or ‘terrorist group’ but the latter would have ruined the surface.
Thanks Geoff!
Geoff: re 17ac: I understand your reservations but, if you read it as IRA VAN = terrorist front, I think it works – very well, in fact!