The elevations are interesting, it really is as near as dammit flat! Bit mountainous in the NW corner...
I recall seeing a few landings on 23 over the years (including a BA 747 with some alarming looking flames while reverse thrust was deployed) but never anything on 05 - but maybe I avoided going to Heathrow when a spending a few hours on the roof of the Queen's Building/T2 would have been in a chilly NE wind!