I'm not sure who is the local expert in the Convict Records you seek ... or, indeed there is left. I always understood the the catastrophic fire that consumed the Crystal Palace in the Sydney Domain, after it was used for the Centenary (1888) Exposition, was solidly credited to the fact that the government had just moved its old archives into the vacant building - and these included all the old Convict Records.
There were many prominent Sydney families in the late boom years of the 1880s that would have paid well for the Convict Records to go up in flames! Obviously, some survived and these are routinely accessed by historians and genealogists at the Mitchell Library, the Australiana collection of the State Library of New South Wales. The general URL for State Libraries of NSW is here and this may help you contact the appropriate section.
Interestingly enough, I have just been asked to add a chapter to a book on one of our really good folk sources here in NSW - Sally Sloane (1894 - ~1982). Sally and her husband Fred Sloane lived in various parts of NSW - Lithgow, some 140 km west of Sydney, when I knew them; 1970 - 1981. Sally passed on hundreds of songs and tunes over a period of years to pioneer folklore field collector John Meredith. I know a bit about Sally's Irish ancestors, the Alexanders, but nothing useful about Fred's Sloanes ... yet!