Well we have been off-line again for about 3 hours early this afternoon but I have finally managed to get version 4.0.1 of our software up and running. The main issue was getting the database to update to the new version. I won't go in to details but it involved some anomalies with the server system configuration.
I now have a little bit of fine tuning to do but that should not involve taking the site off-line.
This is a major update so there may be some slight differences however the general appearance should be the same.
Let me know by PM if you are having any problems.