Some observations regarding the current Forum photo of 5 BSA M.20s
The two machines on the right side of the photo appear to be early machines with the speedo mounted centrally with 8” headlamps and the early rod front brake arrangement. The blackout mask may have a small pilot hole below the blackout hood. The front tyres on both these bikes would not pass a current MOT and clearing in the wet on cobbled roads may have given the soldier 4th from the left on the back tow the need for his head bandage? Note also on the front leading edge of the mud guard the unit has been painted on and none of the machines carry the early front number plate. I cannot see the speedo cable so these machines may have the speedo drive through the brake plate?
The machine in the centre has the offset speedo and drive from the chain case side so appears to be a later model then the first two. It has the Dunlop front tyre and a later type 8” blackout mask with the larger diameter pilot below the mask hood.
4th from the right has a Firestone front tyre – I have one of these on my M.20 marked with an Arrow and WD either side of the Arrow. Also famously marked ‘Gum Dipped’ whatever that meant. The 8” blackout mask appears to be the dame as the first two machines i.e. small pilot hole. This machine seem to have no speedo at all!
Finally the machine on the far left. This carries the later smaller headlamp and blackout mask with large pilot hole and the blackout securing clip. I assume all the others used the screw fixing for the blackout masks as no clips are visible. The front tyre is once again a Dunlop product and I think I detect a front brake rod assembly and possibly the only machine with a hand adjustable side damper knob.
Superb photo with plenty of variations to challenge anyone who fancies being a rivet counter.
Could you perhaps post this on the Forum Ron as an opener and bearing in mind I have been away from the WD motorcycle scene for close on 40 years please feel free to correct any errors.
I have just been having a rummage and have found I have an original copy of:-
Training of Motor Cyclists - Military Training Pamphlet No.24 dated 1939 and issued by the War Office having been prepared under the direction of The Chief of the Imperial General Staff - September 1939.
The pictures seem to vary quite a bit in number, the 1941 version of the pamphlet Keith mentioned says that an instructor should only take 4 to 6 students at a push at any time which does seem to match the number of machines in the pictures so maybe the others were on theoretical parts of the course or just watched and waited their turn?
Another one, with a WD/CO, M20, 16H, M20 and...??? Small headlamp, bulb horn, reminds me of the experimental lightweights. What is this...? A BSA WB30 perhaps?