Hi In the Slot,
I am a Heathrow Controller and would echo what has been said above. We have only about two go arounds a day if that, based on everybody playing the game and vacating the runway as quickly as possible. We can use 2.5 nm spacing under certain conditions, so late landing clearances are common. We also have a "clear to land after" and a "land after" procedure which help to avoid RTF messages to aircraft on short final. The bottom line is minimum delay, therefore we need to pack aircraft as close together as is safe in the circumstances. We will do our utmost to get you on the ground, but as has been mentioned above you have the option of a go around if you (or we) aren't happy with the situation. If you would like to see the operation at close hand please e-mail me and I'll see what I can do.