Agent, having got round Home Counties, is to be still (6)
I believe the answer is:
repose
'be still' is the definition.
(thesaurus)
'agent having got round home counties' is the wordplay.
'agent' becomes 'rep' (short for representative).
'having got' means one lot of letters go next to another.
'round' becomes 'o' (round can mean a round object).
'home counties' becomes 'se'.
'rep'+'o'+'se'='REPOSE'
'is to' acts as a link.
(Other definitions for repose that I've seen before include "take it easy" , "place" , "calm" , "peace" , "State of tranquillity" .)