Those Concorde pilots uh?
Former BA CP, in fact, which makes the huge holes in his proposal all the more surprising.
For a start "
extending both existing runways to the west, towards but not as far as the M25, the length of both runways can be 20,000ft or more" is a physical impossibility.
Extending either of the 27s to 20,000' would take them way beyond the M25, and in the case of 27L would end up in the middle of Wraysbury reservoir.