Search london history from Roman times to modern day
A bit out of date, but this interactive map of step free London is very good
I visited Holloway Road station in July 2019. It is not accessible. It is deceptive because of the lift, but there are also stairs.
All the London railway stations :
Underground lines : Piccadilly
Holloway Road station
Holloway Road station lift
The lift avoids the 62 stairs, and has a message that it transports you to platform level. This is not actually correct, as there is then a slight ramp, and followed by some more stairs to access the platforms.
Holloway Road station more stairs
Accessibility friendly : Holloway Road is not accessible to wheelchair users due to stairs between the platforms and street level. There are lifts, but additional stairs make this station inaccessible.