The Sleeping Tiger: Bogarde's riding abilities

I'm curious, during this period wouldn't the ability to ride horses indicate an upper class background? I found it hard imagining horseback riding fitting into Frank's sordid upbringing.

The character Bogarde plays has been to 'good schools' (says Alexander Knox's psychiatrist) so one could assume (just) that Frank has already-usefully- learned to ride and talk posh and to be arrogant with servants.I always found it hard to swallow Dirk [watch it!] as a low-rent villain because he just seemed wrong, too well-bred and 'delicate',for that sort of part (see "The Blue Lamp",where he had a similar, masked- hold- up-man, role).
In his private life he liked to pose for the camera in riding-kit and can be seen on a horse in some 1959 photos, possibly as publicity for his equestrian-aristo role that year in the film "Libel" but it's not clear that he did any of the actual riding seen in that picture.

By the time the picture came out in 1954,Bogarde was in his early 30s, and looks a bit mature for a tormented youth:his character in the picture is all-too-adult in some scenes, then bewildered, child-like and vulnerable in others.Maybe the film-makers should have used, say,James Kenney,instead of the sophisticated Dirk.