According to this no 228 was built c1830 but no mention of 230
Just seen that 229 and 231 are now businesses, i am definitly going to try and have a look next week if i get a chance .
Camberwell New Road compared to Camberwell Road has fabulous old houses all along it and still very much residential with very little looking like it has changed.
I may be way off (as usual) but The Imperial War Museum is about 5 - 10 mins away from here so the area may have had a military link