I see that there is there is some doubt as to where the trailer originally came from.
To ease the boredom on long motorway journeys around the UK, we often take a note of the country of registration on foreign truck number plates, to see which has come the furthest. Many times the registration plate on the trailer is from a different country to that of the tractor unit. I am not including trucks with the chained on plates that are mainly used on UK registered vehicles.
Apart from anything else, this might explain why many of these trucks seem unworried by speed limits.