Hi Rachael and Casalguidi,
Just copied this from the Perth DPS site.  
"The emigrant ship Simon Taylor sailed from London on April 30, 1842. She was under the command of Thomas Brown and arrived off Fremantle in the Swan River Colony 111 days later on August 20, 1842.
There were 242 passengers in all - 5 traveled in the cabins and the rest in steerage. Of those, 219 were assisted migrants and 18 were Parkhurst boys.
The 18 Parkhurst lads were convicted children from the Isle of Wight and by 1852 a further 316 had been sent to the Swan River and apprenticed to local settlers. Other boys were sent to Tasmania, New Zealand, Victoria and even Norfolk Island.
[Top]     Name               Age  Family/Single  Occupation   Quarantine     Comments
ROSER         William        39          F        Ag. Lab.      27 days      ROSER on Quarantine List & ROSE on Ship List.
ROSER         Diana          33          F          ...         27 days      ROSER on Quarantine List & ROSE on Ship List.
ROSER         Lucy           11          F          ...         27 days      ROSER on Quarantine List & ROSE on Ship List.
ROSER         Elizabeth       9          F          ...         27 days      ROSER on Quarantine List & ROSE on Ship List.
ROSER         Fanny           7          F          ...         27 days      ROSER on Quarantine List & ROSE on Ship List.
ROSER         Mary Ann        6          F          ...         27 days      ROSER on Quarantine List & ROSE on Ship List."
COURTESY OF PERTH DPS
The Roser's were in quarantine for 27 days so that would make them released  to Clarence Quarantine Camp on the 16th September 1842.  Does your great uncle know why Mary and Elizabeth died?  Wondering if perhaps Mary died in birth, could she have been pregnant?  Do you think it is possible that Elizabeth died as she was so young and her mother had passed?
Looking for a list of Gypsy Ships, I always thought that the Simon Taylor left from Gravesend, Kent not London.
Tanya 
