The death of Thomas W Larcombe in Totnes, 1963, records his age as 84, giving a birth year of c1879. Searching Births throughout England & Wales between 1872 & 1882 for Thomas Larcombe reveals only four; only one of which is John W --- John William Larcombe b 1878. (Beaminster 5a/382 q September 1878). Beaminster spans the boundaries of Dorset & Somerset.
Dorset Parish records has an baptism entry for Thomas William Larkin for 1 September 1878, Halstock, Dorset, the son of John & Matilda Larcombe. (https://familysearch.org/ark:/61903/1:1:QJD4-1T54
Thomas appears in 1891 census with his parents, but 1901 & 1911 census seem silent on his wherabouts, likewise any marriage record prior to WW1.
Commonwealth War Graves are silent on his casualty.
It seems a distinct possibilty that the 1963 death is the same Thomas William Larcombe. My advice would be to purchase the death certificate and try to piece back the personal history