Just a heads up:
eBuyer in the UK is selling WD Gold 12TB drives for cheaper than most, and they're retail units. 5 year warranty. Not grey market or OEM. Confirmed by serial number.
Model: WD121KRYZ
https://www.ebuyer.com/806515-…12tb-sata-6gb-s-wd121kryz
Currently ~£50 off, making them by far the cheapest 12TB enterprise drive in the UK right now.