Charles was Commandant Neil O'Brien

In the serie Father Brown, season 1, first ep call The secret garden...he was seriously cute with his ginger hair in that uniform
A decapitated man is found in a garden, and an eccentric American millionaire is suspected when he disappears. But then his severed head is discovered.
Episode number: 1x13
Airdate: Thursday December 19th, 1974

In four parts on youtube :

part 2 : http://www.youtube.com/watch?v=c62jgmJS7Xg&feature=relmfu

part 3 : http://www.youtube.com/watch?v=hoqdb0FMj-Q&feature=relmfu

part 4 : http://www.youtube.com/watch?v=1X8oJFyVIaQ&feature=relmfu