ACDM for inbound flights works best when the departure airport is CDM compliant. The majority still are not. One of the issues is that Europe failed to apply a common standard and set of procedures though so airlines (pilots and ops) have to learn a slightly different process for each airport. In any event there is a representative from the UK Border embedded within the master Heathrow Airport Operational Control Centre so they have forewarning of all movements and expected loads etc.