True rodan, and I've got no answer for that. IIRC LL had approval to do 'land after the departing' and different 'land after' procedures, which were landing clearances when no other airport (perhaps with the exceptions of CC and KK) was permitted to do this. I don't know what the situation is now but the 'big NATS airports' were undoubtedly treated differently by the CAA when the CAA and NATS were a single organisation. What the justifications were I have no idea, no one would say when I asked.