Quidco has a £30 cashback rate for the Microsoft Store when you buy an Xbox One S bundle.
Bundles page (Go through quidco to buy)
Examples after cashback:
Minecraft 500gb £199
1Tb Halo 5 and Gears 4 £249
1Tb Fifa 17 + Controller + Forza Horizon 3 £249
Cheapest bundle is £229, cashback is not guaranteed