Solutions

ACROSS
1 Disdain.
D(ISDA)I+N (Aids anag.)
5 Bear pit.
BEAR+P+IT
9 Crochet.
C+R+O+CH+ET
10 Abalone.
A+B+A+LONE
11 Old master.
(anag.)
12 Theft.
THE+F+T
13 Donna.
DON+N+A
15 Off-centre.
OFF+CENTRE
17 Cuban heel.
(two meanings)
19 Toper.
TO+PE+R
22 Atone.
AT+ON+E (TA rev.)
23 St Andrews.
STAN+DREW+S
25 The same.
THE+SA+ME
26 Amateur.
A+MATEUR (RU team anag.)
27 Diddler.
DID+DLE+R (Del anag.)
28 Theatre.
TH(E)AT+RE


DOWN
1 D'accord.
DA+CC+O+RD (ad rev.)
2 Snowdon.
SNOW+DON
3 Aphra.
APHR+A (Ra(l)ph anag.)
4 Not at home.
NO+T+AT HOME
5 Blair.
B+LAIR (rail anag.)
6 Apartment.
A+PAR+T(M)ENT
7 Protest.
PRO+TEST
8 Trestle.
(anag.)
14 Annie Hall.
ANNIE+H+ALL
16 Fall apart.
FALL+APART (ref. Things Fall Apart by Achebe)
17 Chatted.
C+HAT+TED
18 Book-end.
(straight cryptic)
20 Present.
(two meanings)
21 Reserve.
(two meanings)
23 Sheer.
(shear hom.)
24 Drake.
D+RAKE