Saving you £139 (and that's the offer price - they're usually closer to £150).
Basically, buy a really decent phone, get the not so decent one free to give as a pressie! Win win.
I've had both of these phones and you won't find a more comfortable to hold 5" phone. They're both almost identical in terms of dimensions - the Xperia X is actually slightly thinner in depth despite MUCH better specs than the E5, and also a much better camera.
Both mid-2016 phones.