Some short notes on RC10:
1) Unplug ADSL Line
2) Plug one single computer into the router
3) Give this single PC a static IP of 192.168.0.20 and subnet 255.255.255.0 and gateway 192.168.0.1
4) Open the http://192.168.0.1 web interface and disabled UPnP
5) This didnt appear to improve things
6) In the GUI under the Backup settings I Reverted to Factory default settings
7) Plugged the ADSL line back in
8) Ran the setup wizard which worked, after around 10 seconds
9) Checked I had internet access and now hooked the other machines on LAN back up.