An update of sorts on the problems we're currently having with the site cache, which is causing forum threads to not display the latest posts, private messages to not update and the login status to behave erratically...
The technical team are hoping to have a fix for the issues by tomorrow afternoon (Thursday 25th September). In the meantime, the only 'workaround' is to perform a 'hard refresh' of your temporary browser files (with your browser as the active window):
On a PC: simultaneously press the Ctrl and F5 keys
On a mac: simultaneously press the Cmd and R keys
iPad/iPhone: you can clear history, cookies and data within Settings Safari
This will hopefully cause the forum threads to update, and your private messages, although I can't guarantee it will work for all users.
Sorry for this, I realise it's a complete pain. Fingers crossed for a full fix by tomorrow afternoon - I'll keep you updated.