5miles- our databases are updated on exactly the same cycle that your airspace changes are implemented, as defined by ICAO. These changes can only be implemented on the dates as defined in some ICAO doc or other. It's years since I've looked at things like that so I can't remember the details, but I think contracting states update on a 28 day cycle, (it's the same cycle that AIP supps etc are issued) and have to give 56 days notice of intention to update, in order to give the database suppliers like Jepp time to incorporate the changes into their databases. When our database changes it also updates the stored company routes, so you shouldn't have to do too much explaining on the 16th, except maybe to steam driven aeroplanes without databases.
Alos, there are prnav STARs on trial to LHR as well as to LGW. (Or did you mean an actual approach?)