It’s not anything like 7 years for either the EU or UK (they differ sometimes). It’s two years for a fault which was present at first delivery, i.e. does not cover a product which develops a fault, it is up to the manufacturer how long they cover these faults.
Proving it is another matter. For the first 6months it’s up to the manufacturer to prove it wasn’t originally faulty. After that the customer has to prove that the fault has been present since original purchase.
Sorry to burst that bubble.
Regardless in my opinion if you have just one faulty pixel it shows the product is faulty so you should get a replacement.