I've had 5B, as well as A and C. There are several ways to do it, depending on origin and departure points, but if arriving airbridge into (e.g.) C they can walk you via Flight Connection C and then on to the car; alternatively driven to C65 and up a staircase to Flight Connections, then down again afterwards. T5B you can leave via the bus departure gates, T5A effectively the same, or just along from it, using A10.