Textile worker set up in Surrey docks (4)
I believe the answer is:
dyer
'textile worker' is the definition.
'set up in surrey docks' is the wordplay.
'set up' says the letters should be written in reverse.
'in' indicates the answer is hidden within the clue.
'reyd' is hidden within 'surrey docks'.
'reyd' written backwards gives 'DYER'.
(Other definitions for dyer that I've seen before include "Cloth colourer" , "Cloth worker" , "colourist" , "I change colour" , "Person colouring cloth" .)