sorted the problem a while a go now.....
The NAT IP should of been my WAN IP.
Just as a bit of a 'heads up', there seems to be a problem with the voice mail at the moment. The 'wav' files on the portals' voice mail tab don't appear to be wav files, I cannot find a media player to play them back.
Also, using the SIP phone to access the voice mail doesn't work, the user ID and PIN is rejected. This is the reply I got:
There is currently a problem open on this, this is being caused because the portal servers are not able to talk to voice mail server. For your reference, the problem ID for this is Problem (ID 43146) . We hope to fix this problem very soon, please be advised that your voice mail is not lost and will be available once this problem is fixed.