So I've installed Ubuntu, had a small issue with the LAN driver not working, restarted and this was fixed.
Been re-starting and logging into windows and all has been well. Then suddenly I couldn't connect to the internet.
The network connection seemed to be clicking between 'A network cable is unplugged' and 'Enabled' every few seconds... very strange.
I'll try and write up the process I went through to fix it, but the fix was simply to power down the PC, unplug from the mains for a minute and plug back in and power up. All works fine now.