We had got the gun in central London (4,3)
I believe the answer is:
west end
'central london' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'we had got the gun in' is the wordplay.
'had' becomes 'd' (in contractions e.g. 'I'd', 'you'd' etc).
'got' says to put letters next to each other.
'the gun' becomes 'sten' (British sub-machine gun).
'in' means one lot of letters goes inside another.
'we'+'d'='wed'
'wed' placed around 'sten' is 'WEST END'.
Can you help me to learn more?
(Other definitions for west end that I've seen before include "Fashionable part of London" , "London theatre district" , "London's theatreland" , "London theatre area" , "Part of central London" .)