I wanted to inform you, Donncha of a security issue.
I found this in my cache folder today: /cache/supercache/
As you can see some hackers can create folders in the supercache folder. Somehow. I don't know how they do it, but it needs to be looked into. I believe this can be a security issue. I looked into the folder and downloaded the files, it was my site .. but if they somehow manage to establish a remote connection then it will cache the site and make it accessible. So, what I'd suggest is to add some checks that only subfolders for the domain can be created!
Also, I wanted to inform you that I accessed your site recently and it was downloaded as a rar file. Maybe something you should look into.
Anyway, keep up the great work.