Unclued lights (one of two words) give an event, its organiser, some participants, its winners, and the prizes.
 

Across

1    Stamp hard — everyone notices (8)
8    Men caught by a great beast (4)
13    Men impressed to receive hired waistcoats (6)
14    Elephants’ cup final? (7, two words)
15    Most frightening decay, in a way (8)
18    Measure of alcohol upset, lacking such delicate control? (9)
19    Count food additive out of barrel consumed (9)
20    Bismarck saw head dismissed (4)
21    Accomplished bow by Henry (4)
24    Groans, suffering in parts of body (6)
28    Southern county’s small island (6)
31    Standard recipe for salmon (4)
34    Finely, they discharge old skinflints...