Thank you everyone for your informative replies. I will have a good think about the best way for me to proceed. Probably being naive but I thought that I could connect everything in the dome ie the Pulsar rotation drive, CGX mount, focuser, ZWO camera together into a powered USB hub then via the ethernet CAT 6 cable to the remote PC in the warm room ie just use the Cat 6 cable as a literal extension to my current single pc.
I think I like the sound of the ASlair Plus but need to find out it's exact functions and requirements before deciding. Don't fancy a 2nd Windows PC that's for sure.