One man in a boat turned back to find old address (6)
I believe the answer is:
sirrah
'old address' is the definition.
(historic form of address)
'one man in a boat turned back' is the wordplay.
'one man in a boat' becomes 'harris' (character from Three Men in a Boat).
'turned back' is a reversal indicator.
'harris' in reverse letter order is 'SIRRAH'.
'to find' acts as a link.
(Other definitions for sirrah that I've seen before include "Archaic way to address" , "old man's address" , "Old address for fellow" .)