Thom,
24d, Jack (as in cards) followed by nicked (stolen) missing 1st letter
28a, Non clashing letter missing from a loose description of a fencing
term, support is the definition of the entry minus the missing letter
29d. Another with a non-clashing letter omitted from the answer, Basic
is the definition of the entry minus the missing letter
31a. Remove is definition, another unclued letter entry, and the support
is something used by artists -minus its last letter