Maplin selling plug sockets with USB socket for £4!

Not sure if this is the right board for this, but I've just discovered maplin sell a 13a plug socket with a USB socket built in for £3.99:
http://www.maplin.co.uk/13a-wall-socket-with-built-in-usb-340875?C=34124&U=usbsocket1

I popped out at lunchtime and bought both the ones my local store had in stock.

I'm also had a google and they're way cheaper than anyone else (which is a bit of a novelty for Maplin).

We just need to persuade them to sell Arduino boards now!

Strangely, they sell my book, but not the boards. I have pointed this out to them, but I don't think they were listening.

I wonder if there is a double socket version?

Have you tested how stable the supply is?

There isn't a double socket version and I haven't installed either of them yet.

Not entirely sure how to check the stability of the supply though?