This is the first 12 month deal i could find on this phone.
£73 x12+460 upfront = £1336
This deal may not be hot, as finding hot deals for iphone 7 plus is akin to looking for love on beach when the tide comes in and you're stuck onshore while your gf is stuck on an island...but it is at least a 12 month deal.
Alternatively, given that the average pint of beer in the uk is £3.10, you could buy yourself and your friends 440 pints down the pub...
Just putting this out there. Do with it what you will