Thanks for the reply. Yes, one of the reasons for considering staying on W7 is that the firewire currently works ok on this machine running W7, and as well as reading your post I’ve seen a fair few other accounts of people’s struggles with firewire (and MR) on W10.
This current studio computer is 5 years old and has a pretty good spec , and I love my MRs. My theory is that continuing to run W7 the system would/could/should happily bear the weight of C10, but switching up to both C10 and W10 might possibly create some issues. If + when the time comes to go beyond C10 I’ll look at upgrading the computer and addressing the potential firewire + interface issues.