Sign on door of Lloyd’s underwriter with denture (9)
I believe the answer is:
nameplate
'sign' is the definition.
(I've seen this before)
'door of lloyd's underwriter with denture' is the wordplay.
'door of lloyd's underwriter' becomes 'name' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'denture' becomes 'plate' (I've seen this before).
'name'+'plate'='NAMEPLATE'
'on' acts as a link.
Can you help me to learn more?
(Other definitions for nameplate that I've seen before include "for handle at entrance" , "Notice telling who is the occupant" , "Plaque" , "It may be attached to an office door" , "One identifies" .)