This deal is only available for PS4. (Not XBOX). Xbox one game is priced at £20.23 at Gameseek.com
This game is advertised at £14.73 at gameseek and you can get 5.5% Cashback from Quidco (valid for next 8 days). This will make the effective price £13.91
I can't find this game cheaper in today's date, maybe you can get pre-owned game for cheaper price.