Each singular nurse in part of London (4,3)
I believe the answer is:
east end
'part of london' is the definition.
(I've seen this before)
'each singular nurse' is the wordplay.
'each' becomes 'ea' (abbreviation).
'singular' becomes 's' (abbreviation sometimes used in dictionaries).
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'ea'+'s'+'tend'='EAST END'
'in' is the link.
(Other definitions for east end that I've seen before include "part of the capital" , "Send tea (anag.)" , "Part of London first to see rising sun" , "Side of London associated with Cockneys (4.3)" , "Cockney's part of London" .)