John wrote:

I can't remember when Metropolitan trains went to Aldgate East...

I can. When I lived in East London in the early 1980's, there were a
couple of morning peak services from Barking , with a couple of
corresponding ones in the evening.

There will have been others in the past as well, because the East London
Line was part of the Met and used to have through services (well before
my time).
--
Definitely one of my favourite pictures
http://gallery120232.fotopic.net/p9633104.html
(56 072 hauling an oil train (surprise surprise!) into Helsby in 1985)