Hi Warp,
Firstly, I hope you recover soon and I hope the cops get the silly ***** for dangerous driving. That kind of stuff really pisses me off.
Second, thanks for your corrections. Yes, it was a schoolboy mistake about the primary and secondary TPS being on the same shaft, - my brain wasn't engaged. I did check to see why I couldn't get the correct gap between 'paddle' and roller bearing / lever shaft, but everything checks out OK and I get the same result with the new stepper motor. Perhaps a mounting hole somewhere was drilled slightly off.
Anyhow, get well quickly, and know that your input on this site is invaluable.
Mark