Last two.
2 down - Exposure came from her being seen on extra's horse (7) D?N?O?E
23 down - Old boy and a master who wrote of a promised land (5) O?I?A...
7 down - Moral lesson in paperback about vagrant (7) P?L?E?B
24 across - A bachelor meeting European son that's turned 10? (4) A?S?
The answer to 10 across is Plot - is this Abse?...
4 across - Cynthia's disturbed by a novel about the aftermath of a war (5, 3) ?????H?? Seems it might be an anagram of "Cynthia's", but I'm stumped....