Locks picked by those experiencing scarcity in Barnet? (9)
I believe the answer is:
hairpiece
'those experiencing scarcity in barnet?' is the definition.
I can't tell whether this defines the answer.
'locks picked' is the wordplay.
'locks' becomes 'hair' (I've seen this before).
'picked' becomes 'piece' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hair'+'piece'='HAIRPIECE'
'by' is the link.
(Other definitions for hairpiece that I've seen before include "Switch, for instance" , "rug" , "False addition to existing growth on the head" , "Using switch" , "A wig or switch to supplement scalp covering" .)