"Which give a line of sight difference of 800 feet or less. Which at 45 degrees would be a vertical and horizontal separation of 565 feet. (Change the angle and as vertical increases horizontal decreases so it makes litle difference.)
Which is closer than I would like to be. (I have to admit I was expecting to prove the tabloids wrong.)"
Actually this statement is incorrect - changing the angle to increase the vertical separation and reducing the horizontal separation would enable us to achieve 1000ft between the aircraft and no horizontal separation. Low and behold we have Standard Separation between the aircraft and no cover up nor and senational near mid air collision at Heahtrow.
So changing the angle to increase the vertical separation and reducing the horizontal separation makes a BIG difference in the context of this problem.
Case solved