Could we ask Lewisham to change it back for the greater good?
Not sure whose greater good (maybe yours) but, no thanks.
Far better that motorists are encouraged to stick to main roads rather than using residential back streets.
For a tiny road, Manor Mount (down the bottom anyway) already has an almost unmanageable level of traffic with huge lorries delivering night and day to Sainsburys, their shoppers, an ambulance station and the aforementioned rat runners careering round Waldenshaw Road in the hope of saving two minutes by cutting out the town centre traffic lights on the south circular.