Try http://footplateequipment.co.uk/.I have searched high and low trying to find a leather drivers bag, anyone know of any places that they can be got from?
Not certain about the exact specification for the bags, however the Guards bag had a long shoulder strap whilst Driver's bags have handles. Sounds like yours is a Guards bag - judging by the flag straps in the top flap.Out of curiosity, was there a difference in specification for drivers' / guard's bags?
I acquired one a while ago via a certain auction site (the fact it was very poorly described and that I found it by chance led to a reasonable price!) and it's quite useful as a kit bag for one of my part time jobs...
The one I have has
bardic lamp holder
what appears to be tea-can sized compartment
what appears to be old style working timetable sized compartment
strap / buckle inside (would this be for holding a pair of flags?)