Masterplug GV White USB Socket Twin Pack. 558/6220
Pair of double mains sockets with 5v 2.1A USB's.
Not sure how great the USB charging is on these or any others on screwfix, toolstation etc.
But these are branded and work out cheaper per item than most other places. ( if you need 2)
At Argos too, so pretty easy for most to get.
Hope it helps someone..