Surely that's for the 3D version?
It may have been. I didn't look that closely. But I'd be surprised if my small Tesco's selling 3D Blu-rays. Bear in mind this is the same shop that 4 years ago was trying to sell Quantum of Solace on Blu-ray for £26. No 3D then. I wouldn't be surprised at all if that Spiderman was the standard double disc release. Where I live there's nowhere else to buy them. Tesco knows this.