Have a read through of this thread
https://the75andztclub.co.uk/forum/s...d.php?t=247084
The sign that it was my column causing vibration was a play in the wheel when alternately pressed and pulled repeatedly while holding at three and nine o'clock on the wheel ( if that makes sense ).
While sitting in the drivers seat with the engine off, as I pulled with my left and pushed with my right I could feel and hear a clonk, when I then pushed with my left and pulled with my right I could again feel and hear the clonk.