What a pilot says and what he is supposed to say are two different things! At Heathrow we expect to hear the FL the aircraft is cleared to, the aircraft type and the arrival information they have received. A significant number fail to do this, resulting in repeated and unneccessary R/T calls. If a pilot has been placed on a heading by a previous sector he will usually be instructed to "contact xxx and report your heading".. If he doesn't then again an extra R/T call is required. We need to ask them their type of a/c because airlines are notorious for changing a/c type without changing the flight plan info which is held in a computer. We need to know the type for several reasons, not the least is in order to provide safe VORTEX separation.