Was looking around for hard drives and came across this. I'm unsure if it's a pricing error as it should go for around £530~600 according to Google Shopping pages.
I done some further research on it:
The official product page: http://www.g-technology.com/uk/products/g-drive-thunderbolt
A review from AnandTech: http://www.anandtech.com/show/10738/gtechnology-gdrive-with-thunderbolt-8tb-capsule-review
This appears to be a single drive unit according to the review (I'm confident that the review matches this product).
I'm currently unable to discover what hard drive is inside the unit. Unfortunately the AnandTech review doesn't mention, though a photo shows it is a HGST, which according to wikipedia:
GST, Inc. (formerly Hitachi Global Storage Technologies) is a wholly owned subsidiary of Western Digital that sells hard disk drives, solid-state drives, and external storage products and services.
EDIT1: I just found the 10TB version of this product on the Maplins site, and that goes for £1585.76 ... so I guess it's most likely an error. Worth a punt maybe and hope they'll honor it? :|
EDIT2: Looks like some of their products are riddled with pricing errors. 20TB RAID version of the product is £652.54 :|
EDIT3: Expiring the deal now as people are reporting that if you try to go to checkout it empties your basket.
EDIT4: (11:23am) 4TB version is still available £76.50 on Maplins according to comment, which is also most likely a pricing error. I know the 20TB version is also working as I've tried to checkout, but not ordered.