The things tesco were selling off cheaply were old bundles... :s
I got a £49 vita 3G. People were going nuts, claiming it was £149 in theirs... Yes. It was. Because it was a vita 2.0.
All oled vita. Certain older Wii-U bundles. Most old 3DS non XL bundles. That was all that was sold off.
Not some huge worrying sign of the state of Wii U or Vita. Just streamlining stock.
These sales were genuine. If you go out hunting. Call round. Ask staff, they'll help you find the great stuff.
Someone that I know in Cardiff told me that the mother and son who work at Tesco try to always get ahold of Wii U and Nintendo reduced priced stock so that they'll later sell on eBay. Sure there can be staff members who're polite and may help but not all certainly.