Site of imperial palaces in Bedford, remarkably big town (9,4)

I believe the answer is:

forbidden city

I'm a little stuck... Click here to teach me more about this clue!

'site of imperial palaces' is the definition.
The definition suggests a singular noun which matches the answer.

'in bedford remarkably big town' is the wordplay.
'remarkably' is an anagram indicator.
'big town' becomes 'city' (I've seen this before).
'in'+'bedford'='inbedford'
'inbedford' is an anagram of 'forbidden'.
'forbidden'+'city'='FORBIDDEN CITY'

Can you help me to learn more?

(Other definitions for forbidden city that I've seen before include "Zone in Beijing" , "Beijing tourist spot" , "Beijing Imperial Palace area" .)

I've seen this clue in The Guardian.

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