The outward correspondence of the Governor of WA between 1851 and 1868 can be viewed on 5 microfilms stored in the SROWA microfilm cabinet on level 3 of the State Library of WA. A couple named Bruce & Anne Buchanan have indexed these volumnes. You can find these indexes in folders stored in a cupboard on the left hand side of the door to the SROWA Research Room on level 3 of SLWA. Look for the Name Index in the file(s) that reference your convict. You will then know which letter number(s) to look for on the microfilm.
We now have downloads available for all five of these index files.
The Combined Name Index download below has been created by extracting the "Name Index" pages from each of the 5 files and making it searchable.