Surely that's for the 3D version?
Anyhow the normal 2 disc Blu-Ray is £10 in Asda.
Had another look in Tesco today to check. The shelf label said £22.50 for the 3D version, but it was the standard 2 disc Blu-ray case that was on the shelf in front of the label. I don't think that store has ever had 3D Blu versions of anything, so I think the wrong shelf label and price has been put out.