A Brit somewhere in the Home Counties
I believe the answer is:
ascot
'home counties' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'a brit somewhere' is the wordplay.
'brit somewhere' becomes 'scot' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'scot'='ASCOT'
'in the' is the link.
Can you help me to learn more?
(Other definitions for ascot that I've seen before include "Racecourse with royal associations" , "Tie round the neck" , "sporting event" , "English course" , "Posh racecourse" .)