Matriculated at Clare, 1904. Awarded the Military Cross in 1917, Baynes was from a military family - his father was Rear-Admiral Henry Compton Baynes (1852-1922), and his grandfather Admiral Robert Lambert Baynes (1796-1869). He was killed in action in Flanders, 14 Oct 1918 aged 32 and buried in Hooge Crater Cemetary, Ypres.
Following his death, his family founded a Studentship at Clare in his name to support postgraduate research in the physical sciences.