I have to say I think there was an unusually large number of stations left behind even after clue 5 (as well as Herne Hill and Sevenoaks I reckon Kent House, Beckenham Junction, Shortlands, Bromley South, Bickley, Petts Wood, St Mary Cray, Swanley, Rochester, Faversham, Margate and Ramsgate all still fitted.