Like I say this same problem is happening on the test forums that we have.
The test forums have not been upgraded for 2-3 months or more and is in a password protected directory running on a seperate mysql database. This server also has exactly the same issue making me think this is more a hosting problem.
I have tried upgrading, reinstalling, every trick I can think of.
Do you have any ideas what would cause this from the hosts end?
They did have some routing issues a few days ago and I wondered if this problem could be caused by packets taking a different route back to the the client?
Thanks for your help so far Opserty