This might be a possibility Miss R Day age 19years departure date 24th May 1891 London England going to Sydney Australia Ship Orient ( so that would have been after the census )
Miss Day was certainly on board for Sydney' A report in the
Evening News (Sydney) - 30 Jun 1981 (pg 6), states:
"The Orient Co.'s R.M.S. Orient, with the inward English mails, left Albany at 6.15 p.m. on Sunday. The following are her passengers: — For Sydney.- . . . Miss Day . . ." Then on 8 Jul 1891 the
Sydney Morning Herald (pg 6) reported the arrival of
Orient, with
"Miss Day" listed as one of the passengers.
Unfortunately neither reports provide anything to indicate whether it was
your Miss Day.