I completely agree Rik that there was an official proper correct way of doing things, but we know the rules weren't always followed, sometimes a picture will turn up to prove it, but even then we don't know if an item of insignia on a uniform or vehicle was very quickly afterwards removed on someones orders.
The BSA pictured above is very late war so quite incorrect for the Market Garden opperation he was interested in and I seem to rememder he was dressed as Brian Horrocks at that show riding that machine.
I would quite like to do a Dunkirk anniversay one day on my Big4, but it will have a 1941 serial number so maybe it would be inappropriate?
It certainly would have been helpfull to traffic controllers in combat areas for motorcycles to carry formation signs, but it would also have been usefull to the enemy.
But today its up to the owners to present their machines as they want to, maybe with a written explanation of what is artistic licence.
