Heads on beer in Gloucestershire and Cheshire produced by the main man (3,6)
I believe the answer is:
big cheese
'heads on beer in gloucestershire' is the definition.
The definition suggests a singular noun which matches the answer.
'cheshire produced by the main man' is the wordplay.
I cannot really see how this works, but
'man' could be 'che' and 'che' is found within the answer.
This may be the basis of clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for big cheese that I've seen before include "Mousetrap attraction!" , "Notable" , "Important person (slang)" , "VIP" , "Important chap" .)