Form master at Windsor, perhaps? (4,10)
I believe the answer is:
turf accountant
'form' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for turf accountant that I've seen before include "you bet he wins!" , "bookmaker" .)