Barnet manager, heading off to find artistic finisher? (8)
I believe the answer is:
airbrush
'artistic finisher?' is the definition.
(an airbrush might be used to finish artworks)
'barnet manager heading off' is the wordplay.
'barnet manager' becomes 'hairbrush' (barnet can mean someone's hair).
'heading off' means to remove the first letter.
'hairbrush' with its initial letter taken away is 'AIRBRUSH'.
'to find' acts as a link.
(Other definitions for airbrush that I've seen before include "Artist's device; conceal" , "Device for touching up a photograph" , "Conceal details" , "it's to smooth out the wrinkles" , "Prettify - alter a photo" .)