That's fine Martin. Thanks for that. I've used PHD2 for a while with a separate guide cam and a piggyback scope but always running on ST4 (when it was working. I might try a number of different USB cables - maybe it's not actually a Win 10 driver issue) - I guess I saw the potential of my imaging cam using pulse guiding but I guess I got carried away and thought I could avoid using a separate guide cam for autoguiding.
From what I've read you can use one cam to do both guiding and imaging at once but I guess that's very limited to say the least even if it can be made to work e.g. by having a passthrough (I saw a thread on that somewhere) or by using a dual chip camera and who can afford one of those !
Thanks again for snapping me out of it
I'm overcomplicating it by trying to simplify it.