Perhaps you can add from when has he been missing and a description of what he was wearing at the time, It is evn more important to find him in this really cold weather.

Have you contacted the saferneighbourhood team who also post on this site?

It may also be worth posting this on other local forums such as east dulwich forum and the Sydenham town forum.

The more people who know may help in finding the missing lad. Good luck, I hope he is found safe and well.