That is spot on Alex.
Do you have wire wheels or 5 stud fixing alloys ?.
The reason for asking being that unless the tyre/wheel balancer has the right cones for the wires this can cause problems of imbalance, effectively they are not spinning the wheel around it's true centre if they are incorrect.
I have the Morgan Lightweight Alloys on my Plus 8 they are 16" X 7" Centrelock rims and they need the correct size cones for proper balancing.