When Quatermain arrives in London, he is greeted by Reed who leads him down some stairs. In the shot where they're going down some spiral stairs, for some reason you see a different actor (who is clean shaven) posing as Reed, going down the stairs holding the umbrella in his right hand. Then in the next shot you see the "original" actor who has a slight goatee and is holding the umbrella in his left hand.
Richard Roxborough played Sherlock Holmes in the Hound of the Baskervilles movie. In the LXG movie, Richard Roxborough acted as Moriarty, Holmes's arch enemy.