24a Night at the palladium for guy gone AWOL, last on train? (9) - - L - - - T - N
17d Motion of a particular kind (8) - R - - - I - N
21d Gaul Ali married became pain in the mouth (7) U - - - G - A
Didn't fit but I searched Ulalgia in the dictionary and that's the answer. Thanks for pointing me in the right direction.
Means that 24a is now - - L - A - T - N