The original building is near Gateshead (9)
I believe the answer is:
newcastle
'gateshead' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I don't see?
'the original building is near' is the wordplay.
'the original' becomes 'new' (I've seen this in another clue).
'building' becomes 'castle' (I have seen 'Fortified building' mean 'castle' so perhaps 'building' could also mean 'castle').
'is near' says to put letters next to each other.
'new'+'castle'='NEWCASTLE'
Can you help me to learn more?
(Other definitions for newcastle that I've seen before include "port for England" , "Tyneside city" , "Man City?" , "English city" , "town" .)