I vote for Norbury, where there are no steps down to the platforms - only slopes, which were for the transportation of the horses:
A Victorian racetrack, dating from 1868, held the Streatham Races in the fields (which were the sports ground of the National Westminster/NatWest Bank) that formed part of the old Lonesome Farm. The race meetings attracted huge crowds of racegoers, bookies and other notorious characters. The course also included a water jump across the River Graveney. Sadly, this exciting but disreputable period of history came to an end in 1878 when the Racecourse Licensing Act banned racecourses within a radius of 10 miles of London.