It's not right having more surplus (4,4)
I believe the answer is:
left over
'surplus' is the definition.
(I've seen this before)
'it's not right having more' is the wordplay.
'it's not right' becomes 'left' ('left' is the opposite to 'right').
'having' is a charade indicator (letters next to each other).
'more' becomes 'over' (I've seen this before).
'left'+'over'='LEFT-OVER'
(Other definitions for left over that I've seen before include "Spare, remaining" , "Surplus" , "Not used up" .)