I thought it was for any size wagon aswell but when I drove an 18tonner a freind said I needed to do a tacho, I wasn't taking any risk so did one for that truck, otherwise we don't do them for the 7.5's.
Gary sometimes even the traffic police are unsure, we have a truck that is exempt for restriction, one of our lads got pulled in 3rd lane of motorway as an unrestricted 7.5 can use 3rd lane, Police gave him producer he was looking at 3 points aswell, He told the copper when he was pulled that he could use it, the copper argued the toss, I had to send off a copy of the wagon liceanse with note saying under the current laws etc etc blah blah blah our man got off with it