Composer finding perfect happiness (5)
I believe the answer is:
bliss
I believe this is a double definition.
'composer' is the first definition.
(British composer Arthur Bliss)
'perfect happiness' is the second definition.
(I've seen this before)
'finding' acts as a link.
(Other definitions for bliss that I've seen before include "displaying ecstatic joy" , "Rabbit" , "Sheer delight" , "Highest happiness" , "Rapture; Sir Arthur ---, composer" .)