The one area where my Billingham bags are missing is, they dont stay put at the body when moving around. I commute by bike and the bag does not stay at the back, but slides around. When in the woods in more challenging terrain, or even when bending over to take a pic of something on the ground, the bag always slides to the front. My solution: a "cross strap" as used on messenger bags. This strap makes the bag more stable, it stays where it is supposed to be. With he black Hadley large I split the seams and inserted some webbing with a D-ring. The Pro had a piece of leather hand-sewn on to the canvas. In true messenger-bag fashion, the other end of the cross strap is attatched on the shoulder strap, sliding on it. So one can shift it between hip and sternum, as wished. Its not a perfect replacement for a true messenger bag, as the shoulder strap lacks the quick-adjustment buckle. The Billingham can not been worn as high on the back and still be swung around and opened comfortably to extract a camera. But its a good compromise and means that I can use my two Hadley bags much more often. An alternative to this would be, to attach the cross strap at the pieces of leather the shoulder strap is sewn on. Its ends can be wrapped around these, as they provide gaps originally designed to fit extra pockets. A horizontal cross strap is less than perfect , but works fine for the smaller Hadley bags.