I managed to visit John last week and collect a new shock, well a refurbished one that is.

I enjoyed talking with John and as usual learnt a lot about the workings of shock absorbers.  In the second photo it is easy to see the extra length of the arms on the suspect item.  Apparently it isn't an MGB one though.  Anyway, back on the car and the wheels look to have much better vertical alignment although as it was raining I was unable to take the car out of the garage, maybe tomorrow.