Thanks Chaps, I'll do some documentation tonight. I may have muddied the waters a little, the first issue was the closing door, it was weird and I couldnt see anything, so I removed the chassis connector and it was resolved, I'll post pictures to describe that one better. The second issue (possibly realted) seems to be just when the VFD spins up the spindle as I can have the VFD on spindle stationary and the comms stay up. The VFD is the standard Huanyang variant from China, nothing changed from default, it does make some noise on start-up, the water cooling is active but I guess as its indoors and I'm usually tinkering in the early hours, luckily our neighbour is on holiday :) The reason I'm on USB is the board doesent have the Ethernet module on it, I'll try to source one shortly. It does feel noise/interference currently but frankly the control box was very prototypish anyway with lots of connectors across different faces of the box and the door used becuase I ran out of space, I was planning to move to a larger box and possibly mount the vfd in there also. Anyway, thanks for the ideas, I'll document where I am, look at the ethernet module and see about a bigger box shortly. Three quick questions though..

1). Do folks power the VFD, PSU's and all other CNC stuff (not including PC) from just one 13A wall plug, I'm using the VFD on its own plug right now.
2). For the ethernet SS, do I need to add a router or switch between the SS and PC or will a cross-over cable generally do between them?
3). I would really like to mount the control box on the frame, I've read comments about vibration etc, is it really a bad idea or do some folks find it works ok, it would make my cabling neater and the whole machine would be more compact.

Cheers. Tony.