Also from the Barbour website:
Very similar to the origins of the Gamefair, the Durham is a 4oz lightweight military inspired jacket but darker in style, with the same features. The history of these two jackets is unique and interesting in the evolving story of Barbour. The uniqueness lies in the customisation which changed the end use of a country jacket to a jacket ’fit’ for the theatre of war. Barbour are very proud to be in possession of jackets which were adapted in our customer service repair and reproof department to the exacting specifications of a captain in the Parachute Regimen. Pockets, repairs and strength overlays have been added to the jackets for purely practical purposes. It is both touching and sobering to see the hand written blood group and ranking ciphers on the first aid pocket attached to the inside of the coats. The ‘random’ set-up adds to the aesthetic charm of these jackets which in hindsight are ‘beautifully’ designed.