23a It doesn't allow overnight delivery by traditional route:
?e?t?a? h?a?i?g (looks as though it is central heating but I do not see how it fits the clue)...
1A. Contracting a head in syndicate ?E?C?I?G
20A. On coast, it grows economy ???I?T
16.D Threatened to go out as leader of Government spoke G???E?E?...
32 across: Large cross-stitch in embroidery, 4,5 G?O? P?I??
18 down: Solitary nocturnal feline, 6 ?O?C?? (Looks like it could be tomcat but I did not think that had to be solitary and nocturnal)....