specifically - I would like to know whether the digital drive control box has the correct guide port (I assume it is the same as the EQ5/6 etc).
I also remember reading somewhere about needing optocouplers to isolate different components - is this something I need to worry about with a guide camera,
It should work a treat Adam. While not the same screen, I have the TV Guider which looks to be almost like the beta version. It plugs straight into the hand controller port and guides like a dream. The digital drive doesn't have a dedicated guider port but both the TV Guider and GPUSB work without a problem. Just remember to set the slew rate to 0.3 or 0.5, no more than 2X sideral.
If your in doubt give Steve Massey a call and ask him.