Pretty much RMA time.
How old is it btw?
Also have you tried it in another computer with another PSU and data cable?
Given the drive doesn't exactly (or shouldn't) make any noise, you are relying on the detection of the drive via BIOS and then the OS right? hence, guessing you've ruled out other points of failure too?
Indeedy. It would be useful for these things to have some kind of power indicator. No bios detector on known good controllers/cables etc. If this were a normal drive I would swap the controller board and have a go. Is this an option on these?
Unfortunately not.. the insides.. well.. there's not much to them 
http://anandtech.com/storage/showdoc.aspx?i=3631&p=11 (X25-M but the V won't be drastically different)
How old was it btw?
Well that was exaclty the link i needed to be persuaded not to dismantle the thing! RMA here we go. It is 2 months old and has had minimal use on Win7 x64. Pleasantly fast while it was working though.
Thank you for your help.
