Hi Heathrow Director,
Whilst not having any direct knowledge of the system, I would guess that since there is a record of all landings (for BAA to charge their ever so tiny fees!) and presumably a log of the RVR's then it is relatively easy for BAA to have a clerk or a computer correlate these and send them off. This would not require any action by the controllers, and would also explain how my friend came to be pulled up because a clerk/computer assumed that all landings took place on the "landing" runway
