Sorry, no idea re siblings. I've not found anything in shipping records or in Queensland that mentions Anne had any siblings.
The Queenslander (Brisbane, Qld. : 1866 - 1939) - Saturday 12 July 1879 p.33
DEATHS
TWINE.-On the 10th July, at Grove Farm, Moggill, Anne, relict of the late Job Twine, in her 70th year.
Job c. 23 Feb 1794 Bremhill, Wiltshire
Adam TWINE & Sarah
Fred