Project Cars 2 VR - PQ help

[EdT]

Using an HP Reverb G2, decent PC.

Anyone sorted REALLY cruddy on-track shadows? Ones that lie across the surface created by trackside trees, for example.
I've spent a shed load of time trying settings (in game, in the Steam home, in the config text files, in nVidia control panel etc etc) and everything looks fine apart from these shadows.
Google is filled with 'how to make it great in VR' pages - many contradicting each other... but I've tried them all I think!

At this rate I'll be looking at PS5 & VR for Xmas...