Thanks for the help, I wasn't expecting such quick replies!
I already had a look at the Western Digital My Book Live Duo and the storage capacity is what put me off it. The Synology units seem to be exactly what I'm looking for.
Sorry, yes I meant storage.
Just one question, When it says that is maximum storage capacity is 8 TB, does that mean that the device itself is limited to 8 TB, or that the drives currently available for it are limited to that?