Robert_Charlton - 5:21 pm on Oct 29, 2011 (gmt 0)

Just tossing out an idea... could it be that you've got canonicalization issues? Perhaps a strong inbound link to your IP is favoring that over your domain name, and you're not redirecting it properly to your domain name canonical.

I don't know what other issues you might be having, so this is just grasping at straws in the wind.