Government in spotless country house (9)
I believe the answer is:
whitehall
'government' is the definition.
(street holding many UK government offices)
'spotless country house?' is the wordplay.
'spotless' becomes 'white'.
'country house?' becomes 'hall' ().
'white'+'hall'='WHITEHALL'
'in' is the link.
(Other definitions for whitehall that I've seen before include "Government policy" , "Street symbolising British government" , "Administrators" , "admin staff here" .)