I don't think you are right about a social division. I have lived on both sides of the railway and regularly visit family and friends on the other side. I was also educated on both sides of the railway, so I don't think either side should take responsibility for my poor grammar, and spelling mistakes I leave to Firefox's spell checker.

Some of the most expensive houses in FH are in Allenby Road, Garlies Road and Vancouver Road, and they rival prices on most roads in 'Upper Dulwich Bottom', with the possible exception of the huge houses in Wood Vale.

The social mix on both sides of the railway keeps Forest Hill an interesting place to live. We have more in common across the railway than we have differences.

I don't want to stop some light-hearted digs across the railway line but we should try to keep them in context and add a little smiley face when we are being deliberately provocative. :-)
Sometime people take things too seriously when written down without the proper context.