I keep wondering what could have changed on the car. Could be that all the moving parts are now 'bedded in', so any small imbalance shows up more.
Front wheel alignment is spot on, not changed, and as the problem occurs driving on a flat surface with no bumps or undulations, doubt anything to do with bump steer. The front geometry is more or less as per factory- maybe a bit more camber, but that's about it!
Will refit wheels that are being balanced again and see what occurs. Have asked the guys not to hide the weights behind the spokes! I also marked the previous weights and locations, to see if different this time.....
Could be it has to be lived with Gordon, but vibration is one thing, severe shake another!