youngoldbloke said:If you need one immediately (with postal strike imminent) this is remarkably similar - if not the same (anyone know?) as the Tesco 3 LED rear light, currently £3.30.
Wilkinsons do a set of 1 front and 1 rear light, 3 LEDs each, for £6:57. The rear light looks to be identical to the Smart one (except of course that it doesn't say ;"Smart"). I've got a set I bought a couple of months ago, and I'm pleased with them.
Edit: These are they...
http://www.wilkinsonplus.com/Cycle-Accessories/Wilko-Front+Rear-LED-Light-Set/invt/0258253
Another edit: I think one of the good features of these lights is the built-in reflector which remains fastened to the lens. The 3 LEDs poke through holes in the back of the reflector. Most of the other cheap LED lights don't have a reflector.
And yet another edit: Just to make it clear, I didn't buy them mail order (hefty postage for just one item). I saw and bought them as a bit of an impulse when in my local Wilkos.