I went with what I have to type into National Rail Enquries where it's London Kings Cross and London Liverpool Street and etc etc. Knowing it took the data from NationalRail, this seemed the obvious approach.
I typed in 'WAT' expecting it to match Waterloo (it didn't).
I got Waterloo by typing WAT, it's listed as Waterloo and not London Waterloo
That is probably application logic to help users out, the raw data set of train stations lists the official names only.