Hi Nick. I'm assuming your setup is similar to a Ruby, i.e. with no advance/retard levers. You will need to remove the trafficator and horn multicore cable from the junction box and slacken the pinch collar at the base of the steering box. The bakelite centre and the long tube will then slide up and out. You may find this accompanied by an oil leak from the steering box. The bakelite part is fastened to a circular metal plate brazed to the top of the tube, it's possible the three small screws have loosened. There is also a felt sleeve wrapped around the tube at the top of the steering column which prevents side to side movement - on my car this was missing and the bakelite centre used to vibrate a lot.

Location: New Forest

Many thanks to both of you. I'll have a look at it this afternoon. Nick.

Location: South West France