kingP:
ignore if its a dumb question but.... is it a DCHP lease period type issue?
Should I leave it setup for a few hours in order to be issued a new IP / turn off the UNT for half and hour and start it back up?
At present I have been waiting say 15 - 20 mins then trying again.
No it should be fine. The configuration looks fine also. I'll need more information such as logs from your router to see where it is going wrong...