It was not until 1922, however, now in her mid thirties, that she found major critical success, in Arthur Wing Pinero's The Second Mrs. Tanqueray. Early in her stage career, she was criticised for being too stiff. Aldous Huxley dismissed her performance in Home and Beauty, writing "she is too impassive, too statuesque, playing all the time as if she were Galatea, newly unpetrified and still unused to the ways of the living world." Evidently, her acting improved during this period, as Maugham praised her for "turning herself from an indifferent Actress to an extremely competent one" through her Common sense and industriousness. For both the 1923 and 1924 Christmas shows at the Adelphi Theatre, Cooper played the title character in Peter Pan, while also playing several other roles at that theatre during those two years. She appeared in Maugham's The Letter in London and on tour in 1927 and 1928, in Excelsior (adapted from "L'Ecole des Cocottes" by H.M. Harwood) in 1928, and in Maugham's The Sacred Flame in 1929, also in London and on tour.