How effective are the opening scenes in introducing the characters of Frank and Rita?

In the opening scenes of ‘Educating Rita’, Willy Russell tries to convey a lot about the characters of Frank and Rita, as well as interesting and entertaining the audience, while he does so.
At the beginning of the opening scene, Russell confronts the audience with Frank frantically searching through a bookcase, muttering the names of canonical figures of literature. At the exclamation of ‘Dickens’, we assume he has found the book he is looking for, only to see him draw out a concealed bottle of whiskey and pour himself a glass. After this revelation, Russell uses the medium of a one-sided telephone conversation, with witty remarks about the cooking of ‘ratatouille’. During these first few minutes the audience will have gathered a great deal about Frank, and will have experienced Frank’s rather eccentric personality. From his furtive actions at the start, and the humorous phone conversation, we already know that Frank is an alcoholic, has a dysfunctional relationship, i...