Two groups of pros at the glass face.
One says those who need to know, know.
The others are telling you that, unless they have local knowledge, they know nothing about these standing arrangements.
In particular there has been a history of using low level trigger waypoints that are inhibited and thus invisible on FMC's until aircraft are within, for example, 40 miles of them. Favourites in the past have been ones like GOLES coming in from the North sea or the ones that used to be offered for expeditious right hand downwinds to Stansted's 05. It took years to get some of this trigger waypoints into our main databases.
The proof to controllers is that the fuel plans do not reflect the early drops and the extra fuel. If 20 mins 'no delay' is promulgated for the London area what logic prevents notices for other fields indicating that aircraft must be expected regularly to leave cruise altitude 50, 60 or more miles early?
Without fam flights controllers aren't seeing the difference it makes to arrival fuel for crews without local knowledge.
Regards
Rob