Thanks a lot freerangemonkey and gordon-davisson - very useful!

I'll accept this answer, just want to keep it open a little longer to see what others say.

Thanks for such a cool answer! I hear you re: wake on access- never worked for me so far :). I wondered about cloud-based backup services for the library files and timemachine database, so that a copy is kept off-site protecting against theft etc.

I get to go shopping for a new SSD drive so it's not all bad :) In your opinion what are the chances its not the drive that's died but the Mobo or cable?

Thanks, I found my disc and ran AHT, which gave the error code 4hdd/11/40000000 SATA (0,0) - looks like my HD is on the way out…

Thanks a lot for the input, as Apple say you need an ATV or an Airport I thought it might be filling the same role but I think you're right.