British banker requiring separate note (6)
I believe the answer is:
severn
'british banker' is the definition.
(I've seen this before)
'separate note' is the wordplay.
'separate' becomes 'sever' (severing is a kind of separating).
'note' becomes 'n' (abbreviation**).
'sever'+'n'='SEVERN'
'requiring' acts as a link.
(Other definitions for severn that I've seen before include "Britian's longest river" , "Longest UK river" , "River veers N" , "Nerves (anag.)" , "Gloucester's river" .)