I presume this will only help a few people (with luck).
Asda Corby, went to buy one of these at £15 and it rang up at £7.50, so went and got the only other one left.
It still had normal shelf pricing, albeit at £15, not the usual £20ish.
They don't appear to be on line any more, so they may being sold off in individual stores cheaply.
So not worth a special trip, but if you are in an Asda and they have one on the shelf, it maybe worth seeing how much it is.