The stuff comes in a bowser, generally (5)
I believe the answer is:
serge
'the stuff' is the definition.
(I've seen this before)
'in a bowser generally' is the wordplay.
'in' says the answer is hidden in the clue.
'SERGE' is hidden within 'bowser generally'.
'comes' is the link.
(Other definitions for serge that I've seen before include "Durable fabric" , "Frenchman" , "Twilled woollen fabric" , "Material to suit" , "Twilled fabric; name" .)