I wasn't referring to LHR, I was using the 'runway occupancy' phrase in terms of departures, to which it applies as much as arrivals. Any moderately busy airport will be recording the same data and identifying both potential safety and service delivery trends.
However, we need to be careful when ascribing reasons for a missed approach: For example, if it's due to an arriving aircraft still being on the runway, this can be due to a number of reasons; one of which is a 'late to clear/slow to vacate'. It could be the spacing was poor, it could be that the lead a/c reduced speed too early, or the follower didn't reduce speed very quickly at all, or the lead was unusually light and/or the follower was unusually heavy, or the runway was wet, or the aircraft floated and landed long (which itself can have many causes).