You walk very quickly (especially under a load of shopping)!

It depends whether it is a proper Tesco, or just a "quickie" Tesco. As you say, there is a small one in the petrol station by the traffic lights near the Horniman and also one on Perry Hill, with bigger stores in Catford and Lewisham. But you could also argue that there's a small Sainsbury's in the petrol station near the fire station on Stanstead Road, only a few minutes from either the FH or Bell Green stores.