Scottie - Thanks for the suggestion, but I think I've solved my steering column problems. <
Touch Wood >
As it looks like a previous owner tried to hammer in a new lower bush/bearing without removing the old one first.
So I've got some new parts on order and with a bit of luck I will finally be able to fit the column this weekend.
Note:
I used James Paddock this time as they had the correct steering wheel nut for my "late 1500" in stock.
( It appears Rimmer Bros. no longer list this part, which is why I ended up ordering the wrong nut before. )
Good luck fixing your own problems (with the engine misfire).
Cheers, Paul.