It appears that TCW Hill had two surviving siblings Beatrice Alice and her brother Alf, who she refers to in a memorial notice in memory of her mothers death where she mentions her brother Alf's death.
The Mercury Hobart, Tas. Saturday 18 August 1945
HILL.-In loving memory of my dear mother, who passed away on August 16, 1944; also my loving brother, Alf, who was called home on April.11. 1944. Ever remembered.
(Inserted by Mrs Barlow and family, Melbourne.)
http://trove.nla.gov.au/ndp/del/article/26152231 I have not been able to locate either of their births or births of any children other than a son in 1914, but she mentions family in the notice so I presume there must be more descendants from Beatrice and or Alf.
Robert