Rover P6 front roll centre

[Bellow]

What of a pure trailing arm set-up (where in plan view the pivot axis is normal to the cars longitudinal axis) but in end elevation view that axis is skewed? Any ideas how that is dealt with to ascertain roll centre location?

Still trying to get an answer to the above.
The 'skewing' occurs every time the car rolls during cornering. But yet convention has it that the RC is always at ground level for lead/trail arms. The earlier piece contradicts this as states that the RC does indeed move with skewing of the pivot axis - so contrary to convention.
Is there anyone with a gut feeling of RCs and how this might behave?