At a guess its an Air Berlin 73 on the left and maybe a ford air or private charter one on the right.
Its likely that the Air Berlin is bound for STN, maybe the other is too but prob Luton, there is a point called VATON close to LHR which is prob where their over and heading for BPK and then the arrival for either LTN or STN.
Separations gonna be at least 1000, prob 2000 have been in this situation before ...
hope this helps