This group of what appear to be BSA M20s carry the AoS '68' with Corps bar. This would indicate a corps provost. The location between De Panne and Adinkerke might suggest 103 Provost Company of 2 Corps who are likely to have adopted the '68' serial in line with the other corps during the month prior to 10th May 1940. It's difficult to be certain but the serials may be applied to a plate fixed to the number plate bracket. The image is not terribly clear, but despite a hefty bid, I failed to secure it.