I think the actual question was how to get from Austin Close to Blackheath. The bus stop at Catford Bridge Railway station, where the 202 stops, is a 16 minute walk according to google maps whilst either of the stops on Catford Hill (which becomes Perry Hill) work out at 15 minutes (all are downhill from Austin Close!).

For most of us, this is quite do'able, though as the original query came with a 4 year old in tow, I can imagine that 15 minutes, would be an optimistic dream.