The arrival of Lord Marshmoreton at the cottage stymies Maud's attempt to see George, but also brings a few things to light. Lord M. is of course under the same misapprehension as the rest of his family: that George is the man with whom his daughter is in love. He has been harried by his sister into coming to warn George off, but finds to his chagrin that he actually likes the fellow. More, he finds in George a man he can talk to, unlike his son, who is a pompous idiot. This scene gives us more insight into Lord Marshmoreton's character. He is not simply a figure of fun in corduroy trousers, ruthlessly pursuing slugs across the rose garden; he's a bit of a lonely and wistful soul, cowed by his family into doing things he doesn't want to do and is ill-suited for: writing the family history and playing the heavy-handed aristocrat, for example. He takes pleasure in conversing with George because he can talk about subjects he's interested in rather than about topics he's told he must be interested in.
Of course, what Lord M. doesn't realize is that Reggie's pursuit of Alice is going swimmingly, thanks in no small part to the advice of "Doctor Cupid". One wonders if Alice will want her job for very much longer.