I have the following information about your father and grandfather.
Thomas Clark Deverell b 1856 and d 4 Feb 1941 aged 85 years. By mistake (I was looking for a Thomas Chew Deverell – one of my ancestors) I have a copy of the death certificate of Thomas Clark Deverell. He died on 4th February 1941 at 33 The Embankment, Bedford, UK. He was 85 years and died from myocardial degeneration and senility. He was from 27 Summerhill Road, Saffron Walden in Essex and was a retired civil engineer. His son Alan C Deverell was present at the death and came from Great Barford in Bedfordshire. Quite by coincidence I now live only a few miles from Bedford and Great Barford.
Probate for Thomas Clark Deverell of 27 Summerhill Road Saffron Walden was granted on 31 March 1941 at Llandudno to Alan Clark Deverell dental surgeon. Effects £ 8934? 8s 7d (numbers difficult to read and may not be correct).
George Clark Deverell b 1893 and d 25th June 1915 at Versailles, France. Corporal 723, Essex Yeomanry. Born Bulimba, Brisbane , Queensland, Australia. Son of Thomas Clark and Jane Deverell of Shepperton, Middlesex.
Alan Clark Deverell b 1898 and d Dec quarter 1951. Age 53. Registered at Ipswich. In GRO index
Let me know if you would like a copy of the death certificate. I cannot find any details of the other sons. Perhaps they were born in Australia as George Clark Deverell.
I would be very interested in your Deverell family tree and other information. I have been researching the family Deverell which originates from Swanbourne, Buckinghamshire. To date I have a direct line back to about 1480 and also many other links back to this family.