http://www.yell.com/maps/MapAction.do?route2=SE13+5AX&storePC=SE13+5AX&nat_id=&traveltype=driving&route1=e.g.+postcode+or+street+and+town%2Fcity.&panel=route#route1=SE13+5AX&routeKey1=%3ASE13+5AX&route2=&routeKey2=%3A&points=2&traveltype=driving&units=miles&mapSearchType=routeSearch&scrambleSeed=7491350

Okay so i now have the 'driving instructions' page to where it is and several things were faulty in my mother's account:

She had told me to get to BLACKHEATH STATION and then to go RIGHT out of the station, RIGHT again and then you would be upon BELMOUNT HILL but in fact, his house wasn't on this road but an ajoining one...