75% of display in public was excessive (8)
I believe the answer is:
overshot
'was excessive' is the definition.
(to overshoot is to be excessive)
I can't explain the remainder of the clue.
(Other definitions for overshot that I've seen before include "Went beyond the mark" , "Went past the mark" , "Went too far" , "needed to pull back?" , "Exceeded" .)