Ok, i've been advised by the hosts that the server does not have issues with performance.
What i've done is create a static index.html page that when requested pretty much comes up straight away. So, when you click the link to the forum this is where the time is being taken up.. It also makes no difference if i disable_hooks to the speed.
I've also created a new style that was created with no parent, so no template hacks and this makes no difference.
I've also moved all the attachments to a file system.
It's all good fun this