Good efficient service, especially considering the turmoil caused due the shut down at LHR as the result of a full scale power outage. One minor complaint and it relates to poor signage / direction at T 5. Carpark Level 4. On leaving the lift the only sign says go the collection desk at Zone ‘A’. But no arrow at indicate which direction Zone A was , hence a very frustrating long walk which after a long haul flight was not appreciated. On making enquiries; no seem to know the existence of Zone ‘A’ ……. Perhaps an obsolete sign which needs replacing.As I say a minor point, but worth considering please.