Yes, the accents on the original London cast recording of Les Mis (and in every cast in the UK since) are used to denote class - which is fair enough, because the way you speak *does* tend to pinpoint class as well as geographical origin. In London, it's not a startling choice; Nunn did something similar in his London production of The Baker's Wife, in which the working-class villagers spoke and sang in northern English accents. It's a convenient shorthand (provided the actors can do it), particularly when you need to establish what the relationships are between a large-ish set of characters.
