As far as I can see, Alice is not related by blood to the Mayer family?
Solomon MELLOR (c1898) and his wife Margaret BERRISFORD had a daughter Elizabeth (Betty) in about 1842.
Betty had an illegitimate daughter Margaret Elizabeth MELLOR, born in 1868.
Betty then married Charles PLANT in 1872, and after his death married George Woolliscroft MAYER (a widower) in 1882.
Margaret had an illegitimate daughter Alice Dean MELLOR in 1892, just before marrying John DEAN.
Alice is listed as George MAYER's grandaughter in 1901, but she is (strictly speaking) his wife's grandaughter, and not his.
A John MAYER born c1878 is listed as a "relative" of Solomon MELLOR in 1891. George had a son John from his first marriage born c1878, so it could be him, although he is really no blood relation to Solomon.