Complex sentence: His father (died 1919) was manager of the Menzies Hotel, Melbourne then Hotel Australia, Sydney for over 20 years parents adopted the form'Ure Smith' (his mother (died 1931) was born Catherine Ure) but formally their surname remained Smith.
Split into simpler sentences: His father (d.1919) was manager of the Menzies Hotel, Melbourne then Hotel Australia, Sydney for over 20 years. His parents adopted the form'Ure Smith': his mother (d.1931) was born Catherine Ure, but formally their surname remained Smith.