vectra 2001 1.8 abs problem strange.

[Marks DTM Calib]

Feel free to pop down to Nottingham for a proper check, the live data I am thinking off cant be done on a ramp as you need to drive up and observe the four wheel speed values to see which is low.

[cam.in.head]

silly question but you dont have 1 odd wheel / tyre combination on do you,or even a brand new tyre vs nearly at limit on same axle. could this affect abs readings from sensors as rolling diameter/speed would be unbalanced ?