Hi Pete, As an East End Lad, I can see why you like those railways, Hackney/Stratford and surrounding area was my stamping ground until the 1970s, and being brought up next to the North London Line its always been my favourite (Always fancied modelling Victoria Park Junction), but on moving to Surrey, the 3rd rail and southern Loco's has been my modelling preference - Looking forward to what you decide.
Cheers, Bob.