Travelling with a friend crossing the (none) border from Germany into France, I was okay with the GB plates at the time however my friend with Ecosse on his plate got pulled and was given a warning and his charm offensive about Scotland's shared interests historically against the English fell on deaf ears and meant nothing to them.
Be very careful about ignoring this, there are a lot of jobs worth's out there.
I was stopped in France by the police being on GB plates no doubt ! For not having stickers on my headlamps, unfortunately for their little game mine had been switched to right hand traffic while waiting for the ferry.
I am sure they'll be looking forward to this change with renewed vigor!