 Another younger brother, George Elliston KGStJ MC MA (1875–1954), was a publisher and barrister, and Conservative Member of parliament for Blackburn 1931–1946.His youngest brother Chatterton Eric Elliston (1882–1960) trained as a surgeon but practised as a GP at Porthleven, Cornwall.Sydney Robert was educated at Ipswich School and was a scholar of Pembroke College, Oxford, gaining a 2nd class mathematics Honour Moderations in 1890, a 3rd class BA in mathematics in 1892, and his MA in 1895.