Thank you for all the responses. WD Red it is. Amazon £79 quid. I am now looking at a backup solution so I thought I'd ask the experts. I'm looking at an external 2tb USB. It will only be used for manual backups every week or so. Plug in, copy, switch off, put somewhere safe.
WD Elements for 67 quid perhaps? Or what about a cheap cloud solution? Or is that a stupid idea?
Simon