I have been following this forum since I moved into the Strata building (also known as The Lipstick at one stage) located next to the train bridge and at the southern part of the Elephant & Castle roundabout. Because I love this area so much, I am now settling in SE17, Southwark even though I have moved on from Strata.
I may be wrong but I notice that SE17 postcode has the smallest postcode area in the whole London areas. Just a thought!
I don't know if SE17 is the smallest postcode in London but it would fit in with the original concept of allocation of postcodes which were done in alphabetical order in the Victorian age. So Walworth was given SE17 where Borough being the head office in SE got number 1 ( as did all head offices); Abbey Wood=SE2, Blackheath=SE3, Camberwell=SE5, Kennington SE11 Peckham=SE15, Rotherhithe=SE16 etc. At the time of issuing postcodes Walworth was a small area on the near outskirts of London which did not reach to the far flung places such as Sydenham which subsequently got the non-alphabetical postcode of SE26.
I'm sure you did not need to know all this, neither do other posters, but there may be one person out there who finds it interesting.