© Jan Sebaoperating as flight BA232 from Moscow. It made a normal approach over north London and the City, but while all the other planes were landing on the northern runway (27R), BA232 headed down to Battersea and joined the approach to the southern runway (27L). But as it passed over Putney Bridge, it turned right and headed back towards the 27R approach.
I suspect that Air Traffic Control may have had problems fitting it into a quite busy stream of landing aircraft, not helped by BA232 flying about 20-30 knots faster than the ideal approach speed.
From the track plotted on casperflights.com, it looks as if the nearest it came to Langley Drive was over Kew Railway Bridge, about 1½ miles from you, but I'll have a look at WebTrak tomorrow to get a more accurate path. It was certainly nearer to you than the normal landing path, as it overshot the 27R runway heading, hence the tight turn to the left that you saw.
If you go to
http://uk.flightaware.com/live/flight/BAW232/history/20140808/1315ZZ/UUDD/EGLL and zoom in on the London end of the flight, you can see the path that this flight took, which was certainly unusual.