No opinion on the accuracy but there are numbers out there [1] that an hour or more is pretty average. Not London, but I live about 40 miles out of a major city in the Northeast US near a commuter rail and a major highway and it takes me a good 90 minutes+ if I'm traveling into the city for the day either by train or car. (I did actually commute about half-time for about 18 months at one point.)

[1] https://bmmagazine.co.uk/in-business/londoners-commute-74-mi...