Have you replaced the ARB or steering rack bushes, sounds like it could be slight movement in the rack perhaps in that it tracks one way then the other?
Your alignment and specifically front toe settings appear to be set up ok on your print out.
Have to say, No. 63 looking great now Nick, definitely worth the spend to bring it back from the brink. I've just shelled out similar on No. 407 on fairly routine upkeep, but worth every penny to keep it driving as it should. 👍
I've not heard of any issues particularly, though after a bit of looking online there seems to be some very mixed reviews/ experiences from folk dealing direct with the company, seems either brilliant or a bit rubbish... Food for thought.