I've got three "answers" which I can't parse. 21a Party after supporting seat (8) B?C?S?D? I think it's BACKSIDE but the rationale seems quite thin. 23a Lovely drop, in parts (6) ?I?I?E I'm thinking...
2d Bingo's a bit of a laugh (3) A?A (I'm thinking AHA but is this the equivalent of BINGO!?) 22d Sweet child with its foot in Rhine on vacation (5) T?R?E (Could it be TORTE, which is a sweet, formed...
17a First of editors on the Times to make history (5) ER?S? (I can only think ERASE but the definition seems wrong.)
16d Turn up with possible substitute for stick: carrot? (4,4) ?O?T?R?P...