Solutions

ACROSS

1 Artefact.
ART+E+FACT
5 Patter.
PAT(T)ER
9 Cartland.
C+ART+LAND
10 Tidied.
TI+DIED
12 Siena.
SIEN(n)A
13 Rotterdam.
ROTTER+DAM (mad rev.)
14 Ball and chain.
(two meanings)
18 Reaction time.
REACTION + TIME
21 London Eye.
(straight cryptic)
23 Aware.
A+WAR+E
24 Portia.
PORT+I+A
25 Matiness.
MAT(IN)ES+S
26 Ending.
END+IN+G
27 Heathens.
H+EAT+HENS


DOWN

1 Accuse.
(C+CAUSE anag.)
2 Turned.
T(URN)ED
3 Fall apart.
F(A+L)L AP+ART
4 Control tower.
CONTROL TO+W+ER
6 Arise.
(hidden)
7 Third man.
(anag.)
8 Rudiment.
(Rudy meant hom.)
11 Stand the pace.
(anag.)
15 Campanist.
CAMP+A+NIST (tins anag.)
16 Prolapse.
PRO(LA+P)SE
17 Mannered.
MANNER+ED (de rev.)
19 Varese.
(anag.)
20 Versus.
VER+S+US (rev rev.)
22 Orion.
O(RIO)N