You may be lucky to find them at Argos - my local ones (including Argos Extra) have been out of stock for weeks!
I saw one in GameStation a month or so ago for £18. 'Wish I'd bought it then as it was gone a few days later, and I couldn't find one in Game, HMV, Zavvi, Argos, Woolworths (!), or Amazon. The ones on Amazon for £40 are not being sold be Amazon, as they seem to have been out of stock for weeks.
Either more PS3 owners have been buying Blu-rays, or as a result of Sony bundling the remote with the PS3, but there does seem to be a shortage at present, and some dealers are cashing in!
But you're right about Game's website - I've just ordered for £15.11 (including Reward points discount)! Thanks!