I often get the feeling I'm the only one modelling the SR pre WW2, especialy in N gauge, obviously there must be some or there would be no RTR nor kits for the SR in that period. Very few shows I have been to have featured SR in 1920/30s; where do the rest of you hide, I know of a few in 00 gauge but not in N; Southern layouts featured on forums always seem to be set post WW2.
I model a fictitious junction and shared running harbour on the Southern end of the SDJR, at the end of the prussian blue era. There's Southern, LMS, GWR and SDJR stock. And a seasonal once-daily cross-country teaks from Newcastle for the Channel Islands.
So, erm, everything.
I think in about 10 years time you might be lucky to see BR Blue still being modelled at exhibitions.
Southern in the 20/30's is far too modern for me ;)