Getting this back to what I think was the original intention - identifying holes in specific areas - anyone modelling the cross-London lines in the transition era (as I just happen to do) still needs:
SR C2X, W and Q classes
ER J6, J17, J19, J20 and F5
LMR Fowler and Stanier 2-6-2Ts, Midland 2F and Tilbury Tank
WR 97xx condensing tank
+ Oerlikon, Watford or 501 EMUs.
and doubtless a couple of others I’ve forgotten.