Cheese supplied by average guys going round South Africa (8)
I believe the answer is:
parmesan
'cheese' is the definition.
(Parmesan is an example)
'average guys going round south africa' is the wordplay.
'average' becomes 'par' (average score in golf).
'guys' becomes 'men' (guy can mean a man).
'going round' means one lot of letters goes inside another (some letters go around others).
'south africa' becomes 'SA' (abbreviation).
'men' going around 'sa' is 'mesan'.
'par'+'mesan'='PARMESAN'
'supplied by' acts as a link.
(Other definitions for parmesan that I've seen before include "Spearman (anag) - cheese" , "Italian cheese, often grated" , "Cheese for grating" , "that grates" , "Italian 8 across" .)