He’s back! The Samsung Evo 64GB class 10 microSD card is available once again from Amazon - dispatched and sold by Amazon - for £20.86. With the RRP being £55.49, that’s a delicious 62% off.
This is the ‘64GB without Adapter’ option. Grabbing an SD adapter will bring you up to £23.28 (sold by Locoisle777).
(Thanks to brraven and SixtyFive at HUKD)