I would love to model 1960's electrics but there is nothing. Dapol will probably not release an 86 in 60's livery and I was hoping that Farish would release their 85 in N Gauge this year, may be they will next year. One problem causing the low sales is that if you wanted to create a layout with electrics you need more than one class to do so. The Farish 87,90 and 91 are not up to current standards (detail, dcc, lights etc) so all you have is a decent 86. With the liveries available you can only model the late 1970's onwards. There are no overhead wire EMU's for the period 1960-1990's either.
The same argument goes for Southern EMU's. In N gauge there is only the CEP and the Arnold Brighton Belle next year. You can't satisfactorily create a Southern Electrics layout with only these 2 models. In OO it is now easier as there are at least 6 types of EMU available EPB,CEP,VEP,Thumper, Brighton Belle and MLV.