MODEST UPDATE : Removal of Nero s/w and un/re-installing drivers for the two drives means that :
CD (only) burner will now make CDs - whoopee!
CD/DVD combo burner will ONLY make DVDs - sort of whoopee!
I've had enough with all this - what works, works - I can survive with that - using the InfraRecorder s/w
Thanks for all comments and ideas ..
Rob