Oh dear! Looks like i spoke to soon. Took the car to work (65 miles) and as soon as the speed gets up to about 55 the noise and vibration are back. I thought the noise was from the front but it is now definitely from the back which would tend to indicate that it's a tyre problem. The noise improves to a above 60 but is still there. It's almost like a resonance stes up. It has quietened down a bit but is definitely still there. Unfortunately, I took it for a drive with the tyre dealer and it didn't really do much but he has agreed to change the tyres if it doesn't improve. I have noticed that they fitted reinforced (102 load rating) instead of the 98s that i ordered - is this likely to make much difference? In addition, the last couple of tankfuls since the new tyres have given 33 mpg, much less than the 38 I was getting and the car feels a bit like the brakes are partially all the time. It has just been serviced and they said the VCU was ok but I can't help thinking it is all connected.
Changing the tyres seems to be the obvious route but anyone got any other ideas or is it all coincidence!
Cheers