Here's a lead. No guarantees.
http://nla.gov.au/nla.news-page8444365WALSH. On the 2nd November, at the residence of her granddaughter, Hindmarsh, Catherine Walsh, aged 85 years. Arrived in ship Mary Ann. 1849.
http://nla.gov.au/nla.news-article207756224THE FRIENDS of Mrs CATHERINE WALSH, late of California-street, Adelaide, are respectfully Informed that her Remains will be removed from her granddaughter's (Mrs. WilliamWare, jun ) residence, Osmond-street, Hindmarsh, TOMORROW, at 3.30 pm, for interment in the West-terrace Catholic Cemetery.
Associated
conjecture (see opening sentence) follows.
Since the granddaughter's husband was William Ware junior, his father was also William Ware. This is consistent with her husband being William Edward Ware, and hence the grand-daughter being Charlotte Annie.
https://bound-for-south-australia.collections.slsa.sa.gov.au/1849MaryAnn.htmAt her death Catherine Walsh was the widow of Peter Walsh. They are presumably "WELSH, Peter and wife and 4 children". Both a James Roach AND an Edward Roach are also listed as passengers.
It was pretty common for immigrant ship passengers and/or their close relatives to marry after arrival.
If Charlotte Annie Roach was the grand-daughter of Peter and Catherine Walsh then her mother must have been a Walsh.
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Note 15 Jan (South Australia) - I corrected "James Webb Roach" to "James Roach"