A quick search on
http://ndpbeta.nla.gov.au/ndp/del/article/3665145?searchTerm=de+chastelshows young Claud DE CHASTEL of Mt Morgan won a scholarship to a Grammar School in 1898.
1949 Queensland Electoral Roll
DE CHASTEL Alice Elizabeth Mary 68 Bolsover Street, Rockhampton Home duties
DE CHASTEL Angelo Carroll Crescent Grange Soldier
DE CHASTEL Evelyn Annie Carroll Crescent Grange Home duties
DE CHASTEL John Henry Carroll Crescent Grange Student
DE CHASTEL Ronald George Carroll Crescent Grange Dispenser
DE CHASTEL Vincent 68 Bolsover Street, Rockhampton Labourer
I noticed there is a Claud who married in NSW.
7114/1938
DE CHASTEL Claud Henry
PIGGOTT Delina Floraline Jane
District Rockdale
and their deaths
http://www.ryersonindex.org/de CHASTEL Claud Henry
Death notice 22APR1991 Death 79 late of Turramurra Sydney Morning Herald 23APR1991
[Claud b 1884 son - Qld births
1911/C10518 DE CHASTEL Claud Henry
Father Claud Mother Vera Josephine Lude]
de CHASTEL Dell Death notice 27DEC1978 Death late of Turramurra Sydney Morning Herald 28DEC1978
There is a facility on the website to request copies of the death notices.
Cheers
Cando