Graham, are the balancing weights on the outside rim or inside? I ask because I recently made the (fashion) decision to have my wheels rebalanced with the weights on the inside. I was told by the fitter that it would need "static" balancing as opposed to "dynamic" balancing, and that I would be back to have it switched back as its not as good. I do have vibration fro 68-75 mph, but its OK above this circa 85 cruise, and below. I went back and asked if they used the correct balancing cones, and they said they have them all and couldn't mount wires without them. I'm not sure what it all means, but I may try somewhere else, so will be very interested in your results.
Where did you go? I always use Thrupp Tyres and they've never had a problem balancing my wires.