Pretty much what he said!
Within controlled airspace, the only service available is radar (or sometimes procedural) control, and the clearance usually comes in the form of "cleared from a to b via c, at/not above xxx feet".
LARS is only provided by LARS units (a list and diagram is in the AIP and in the RAF BINA), the units being military or being subsidised by the state to provide the service. Other units will usually provide a similar service beyond their airspace boundaries, subject to controller workload.
The controller may have said squawk 7000, freecall London Info, but there is nothing to stop you from calling a different unit (eg the next suitable), or indeed from saying "I'd like to remain with you for the next xx miles (or until a place)" etc. Just bear in mind how busy the freq is if you ask!
ap
