In shop Tim accepted most favourable points (6)
I believe the answer is:
optima
'most favourable points' is the definition.
'in shop tim accepted' is the wordplay.
'in' says the answer is hidden in the clue.
'OPTIMA' is hidden within 'shop tim accepted'.
(Other definitions for optima that I've seen before include "Points at which conditions are most favourable" , "Conditions producing the best possible results" , "Ideal conditions" .)