Well, we've just been alotted a new set of IP Addresses for the server that we pushed through this AM (having only 2 hours sleep!).
I had a small problem which caused a 2 hour downtime due to a 4 minute edit lol; it's up and running now though.
Our old subnet was: 38.99.95
Our new subnet is: 68.68.100
The technical details of the problem where that I did not go in and check the interfaces manually; i trusted Webmin had updated them for me in the config options in the control panel...
Lesson: always double check, otherwise you get to learn how to use a virtual console and alternative text editors just trying to get things back up and running, and it'll take you 3 hours lol...
But all is changed, all is fixed, all is fine!