Hi Chris Sorry, no luck locating death. On checking deaths for Thompson in 1852 (when he was widowed) located a Sarah, age 23. (Age fits but no parents recorded). On checking marriages - a William Thompson married Sarah McKenna in 1848 - 2 entries - Registration Nos. 40608 and 584. Son (William) born to William & Sarah McKenna in 1849 and a daughter (Catherine) in 1851. Each of these entries had denomination as Rom.Catholic and the Parish as St.Francis, Melbourne. Strangely, every entry was duplicated with different registration numbers. Could be a long shot that this may be your William.. Only way to confirm would be to purchase the marriage certificate, but this could turn out to be a waste of money. Not sure whether parents were recorded on certificates back then. Good luck Joan