Having felt challenged by the above I have been digging around unsuccessfully for some months. Then this morning I was just sitting at the computer waiting for my wife and grandson to get ready so that I could take them to work and school when I made a breakthrough. I just don't understand why I hadn't found this before but on ScotlandsPeople I located his record of death. He died outwith Aberdeen (which may explain why I'd missed him before) at Dyce on 19 February 1940. He died of a haemorrhage from a duodenal ulcer. The record shows him as a Private in 10th (HD) Battalion, Gordon Highlanders. The informant was his wife, Jane Calder.
This enabled me to search for his marriage which I discovered took place in Aberdeen in 1927. Interesting that his occupation then was recorded as Private (Gordon Highlanders). Encouraged by all this I managed to find a 1938 newspaper report that he had been imprisoned for two months for failing to support his two children. Following up on this there seem to be a number of likely children on Scotlandspeople. The nature of his death and identification of his wife suggests that he was buried. That being the case his grave would qualify for war grave status if it could be located
whereas at present he is commemorated on the Brookwod Memorial in Surrey. There are at least 200 precedents for graves being marked by the CWGC subsequent to commemoration on the Brookwood Memorial.
I feel quite guilty, as you have obviously put a lot of work, and thought into this search - but I am going to have to dash your hopes, I'm afraid.
The parents of George Harold Russell Bell were Henry Bell, born about 1870 in Seaton Delavel, Northumberland and Elizabeth Jane Hardy, and not Elizabeth Biddell as mentioned on the death certificate you found - sorry
Elizabeth Jane Hardy married Henry Bell on 02 September 1895 in Prudhoe, Northumberland, and she died on 06 March 1945 at Howtel, Northumberland.
The mystery of her children - George Harold Russell Bell, born 29 September 1896 at Ovingham, Northumberland and Mary Elizabeth Hardy Bell, born 02 October 1897, also at Ovingham, Northumberland - remains