He really likes a cash surplus (5)
I believe the answer is:
'he really likes' is the definition.
(I've seen this before)
'a cash surplus' is the wordplay.
'a cash' becomes 'l' (The pound sterling symbol is an elaborate L).
'surplus' becomes 'over' (I've seen this before).
'l'+'over'='LOVER'
(Other definitions for lover that I've seen before include "Paramour" , "Romantic partner" , "One of a couple" , "One enjoys" , "toy boy" .)