John Besley in Devon rings a bell - mamod and wilesco conversions to a very high standard if same person ?
Not sure what you mean by a fully threaded rod. Can you post a picture please?
The early TE1 smooth canopy model I have has a rod that goes through the front axle with a retaining nut to keep in place.
The TE1A I have has a rod with tapered hex nut that screws onto the steering rod which is inside the chimney
These are the only two types that I know of.
Stuart