Re: Bump Steer - what I never fully appreciated.
Found the problem with the steering wheel twitching over bumps and it was my fault. When I installed Roll Centre Adjusters I neglected to install similar spacing to the tie rod ends. This weekend I removed the RCAs and took it for a drive and the twitching over bumps was gone. So I think I have misled people who probably presumed that the tie-rods were also spaced, as only a dope would do the control arms and not the tie-rods.
RCAs are really overkill for a road car, much more relevant for track use. I'm going through the exercise as the car is a project for my son (and I) to learn about cars.