These two cards are fighting in two different leagues as GTX 1080 is a high end, high performance product, while the Radeon RX 480 is affordable card which sells for $199 for 4GB version and $239 for the 8GB flavour. Overclockers had enough RX 480, Polaris 10 based cards to make Radeon of Iron Thrones complete with a Khaleesi and a couple of [stuffed] dragons. Remember this is just the UK market so the myth that anyone had a shortage of cards sounds like someone was listening to a spinner.
OcUK has an exclusive on 4GB Sapphire Radeon RX 480 4096MB GDDR5 PCI-Express Graphics Card and is selling it for £188.99 inc VAT
Sapphire Radeon RX 480 with 8GB is selling for £219.95 inc VAT and both cards are currently in stock.
HIS, XFX, Asus and Gigabyte are available and you can find them at the OcUK forum.
OcUK confirmed to Fudzilla that they have a stock of Radeon RX 480 4GB (uk exclusive) and the Radeon RX480 8GB cards listed above. The company also has plenty of Founders Geforce GTX 1080 and some Geforce GTX 1070. They have some custom partner cards in stock and 50 different GTX 1080 skus and around 45 1070 skus.