Anyway found a Macbook USB-C charge cable for £5 which may work for battery operation- for this portable setup I have loaded most of my normal apps with the exception of Maxim / TSX but am additionally reviewing some lighter apps for use with EOS.
Using Win10 Pro - SGP - PHD2, with Nebulosity, C2A, PinPoint, APT, PoleMaster, CCDTools and Connectify and ASCOM loaded - take up 20GB.
Thanks for the tip on Connectify BTW. It is really useful. I also didn't realise the distinction between Adhoc and AP. Adhoc WiFi uses slower rate than access points. It makes remote operation less sluggish. I shall use it on the NUC too.
Using Windows Remote Desktop - it seems to work fine without a dongle. I was powered for four hours and nothing seems to have hibernated. (I haven't hooked it up to the mount yet though)