Cryptic across
1 Midpoint of an OT empire? (6)
4 Boy, with setter aboard, makes for OT summit (6)
9 Historian implied American connection (7)
10 Eventually let Brexit leader in London borough (5)
11 Old West town from a Mailer novel (7)
12 It’s Amos’ place to enumerate koalas passing through (5)
13 Confined state planned and accepted by Huguenots? (5,2,6)
16 He met his maker, being single, returning to church (5)
18 Care about a Norman abbey in a Hitchcock feature (7)
20 Port Paul used needs visa, or ticket, to travel back through (5)
21 Tack 180 degrees after a short time in classical Italian islands (7)
22 Ceremony where habit is required? (6)
23 Court game one from place in Co Clare after date number three (6)