came across this box at a local classic car show / autojumble the other week. the last time I saw something of the ilk was at the D-Day show at Portsmouth in 1989. a chap had one on the bonnet of a Jeep but the end closure was different, it had two, "handwheels ". I made a brief note of the markings, C286 II, BMB 44. The length was 30 ins. Box C264 is a few inches shorter. I believe that when the 6 PR APBC came on to the scene ( anybody know the date of introduction ? ) it was too long for the earlier box, hence C286. I also assume they simplified the end closure method of fastening at the same time. BMB , Briggs Motor Bodies, AS & S don't know.