Just been to my Local Tesco (Sunderland) and the guy gave me a coupon for £5 off any electronics. They were just laying on the counter so you could just pick them up and use them. The two games that I got (that he put through as separate transactions so i got £5 off each game) were:
Call Of Duty Advanced Warfare (XBOX One) - £27.00
FarCry 4 (XBOX One) - £39.99
However he said that you can use the coupon on any games in store.