Badly buckled Comet was the cause of vibration.

[foammanmark]

Whilst my R was at the bodyshop, they checked my wheels and realized that a back one was badly buckled. I knew the car wasn't right with bad vibration at certain speeds but I just couldn't suss what it was. Now my spare Comet is on the car, it's made a massive difference for the better with the car being a very smooth drive indeed. Lucky that I had a spare one or else I would have been jiggered.