C E (Charles Ernest) Jacomb was born in 1888. He was certainly alive in 1959 - his brother Edward updated his will that year and names him in it. It looks like C E Jacomb died in 1961 - there's an entry in the deaths index that year for a 'Charles E. Jacomb', aged 73 in Paddington. Hopefully someone here will be able to confirm whether that is the case.
A slight correction to your posting: 'Torment. A Study in Patriotism' was published in 1920, not 1928.