After severe 'attacking' yesterday I am pleased to report that Malwarebytes shows 'no infection' although the 'drivers' folder is still reappearing on reboot, so at last some more progress.
MWB have responded to my emailing (thanks GG) and are looking at the logs.
One (extra!) lesson I have noted is that if you run Combofix (having turned off sys restore) it 'restores' sys restore as part of its process. Worth watching.