Swell couple coming over too much (7)
I believe the answer is:
surfeit
'too much' is the definition.
(a surfeit of something is too much of it)
'swell couple coming over' is the wordplay.
'swell' becomes 'surf' (I've seen this before).
'couple' becomes 'tie' (both can mean to join).
'coming over' says the letters should be written backwards.
'tie' backwards is 'eit'.
'surf'+'eit'='SURFEIT'
(Other definitions for surfeit that I've seen before include "Fustier (anag)" , "excessive amount" , "Overindulgence" , "Superabundance" , "Excess, glut" .)