Home Counties guy across the Channel composed (6)
I believe the answer is:
serene
'composed' is the definition.
(I've seen this in other clues)
'home counties guy across the channel' is the wordplay.
'home counties' becomes 'se' (Home Counties in the South East of England).
'guy across the channel' becomes 'Rene' (common French name).
'se'+'rene'='SERENE'
(Other definitions for serene that I've seen before include "Impassive" , "Fair" , "Calm and relaxed" , "Calm, peaceful, tranquil" , "still" .)