This is a non starter and i suspect part of a plan to look at all options before ending back at square one with the only sensible one which is R3 at LHR, by which time it will be kicked into the long grass for who ever wins the next election.
Borisport is a night mare, not to build, that's just (a lot of) money! the big problem is that it will only work if 99% of traffic moves to it from LHR that will only happen if you shut LHR. You are then left with 10's of thousands of airport workers who live in the sit holes around LHR to get across London every day unless you plan to move them?
Heathwick? so you are flying to the far east from the US do you transit by way of FRA,CDG,AMS or Heathwick?