His services come at a premium (7)
I believe the answer is:
insurer
'his services come at a premium' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
(Other definitions for insurer that I've seen before include "One providing cover" , "one will provide cover" , "Provider of a security policy" , "Is rerun (anag)" , "One paying out in event of damage" .)