Hi,
I too have a RHD car and just checked the original engineering report to find 5.1mm bump steer that's sum of both sides. Full compressing to full extension (they remove the springs). So in your case about an inch a side. Rides great no effect on steering no matter the road surface.
There is a mod to fix that. Otherwise look at your idler and pitmen arm
Thanks for the specs, I haven't measured mine in compression but static to full extension is much more than 5.1mm. I will jack it up and take some measurememnts so I know what I am dealing with.
The attached photo is the before and after the work I had done. It is with the suspension unloaded and shows what the left wheel is doing with the right wheel set to point straight ahead.
The mod I had done was to the idler and pitman arms which moved the whole steering assembly up about 2 inches. This made a big difference but when you unload the suspension over a hump in the road it momentarily loses composure. Not enough to be dangerous.
What is that the mod you are talking about?