I think I've got him!!!!!
Looking at his attestation on Ancestry pointed to by PatLac he gives the 9th December 1901 date of birth that matches his 1939 entry. His place of birth is Newark, Peterborough, Northamptonshire. I didn't know that there was a Newark near Peterborough!
I started to work my way through the boys on the 1911 with Newark, Northamptonshire as their place of birth. Any that could be accounted for by a death or appearance on the 1939 register I set aside and moved on to the next.
Richard Gilbert Pitchers is the son of a former horsekeeper George Pitchers, has a brother Fred and a sister Rose. He married a woman whose maiden name was Markson. I can't find any record of him after this 1926 marriage.
He appears as Gilbert Pitchers in Woolpack Lane Whittlesey 1911 with widowed father George, at this time a general labourer, and siblings Leah, Priscilla, Lilian, Fred and May.
From freebmd:
Births Mar 1902 Peterboro 3B 218
Pitchers, Richard Gilbert
Births Dec 1907 Peterboro 3B 188
Pitchers, Bertie Fred
Births Sep 1904 Peterboro 3B 213
Pitchers, Rose Priscilla
Jumping back to the 1901 father George, born Banham Norfolk, is working as a "Horsekeeper on Farm" at Newark, Peterborough Without, Northamptonshire.
Gilbert Pitchers in 1921 is at Landi Kotal Camp, Khyber Pass, North West Frontier Province. He is a Private in the Northamptonshire Regiment.
Back at Whittlesey in 1921 father George is with the children that have not yet left home. There is also a widowed Housekeeper, Lucy Mabel Bellamy and her young son Harold Sidney Bellamy.
From freebmd:
Marriages Sep 1926 Whittlesey 3B 1362
Gilbert R Pitchers + Lucy M Bellamy
Births Mar 1915 Whittlesey 3B 913
Bellamy, Harrold Sydney (mmn Markson)
Marriages Jun 1914 Whittlesey 3B 1305
Herbert S Bellamy + Lucy M Markson
Herbert Bellamy was killed in World War one.
I haven't been able to find anything else on Richard Gilbert/Gilbert Richard after that 1926 marriage to his father's housekeeper.
Lucy by 1939 I think is with a George H Kennelly at Redbrick Farm, Newark, Peterborough. They are shown as being married but I've not yet found the marriage. She seems to have 'lost' a few years from her age given in 1921 but there is a Kennelly daughter with them and this girl's 1938 entry on freebmd has the mother's maiden name given as Markson.
Lucy is a bit of a mystery too. The green ink on the 39 indicates that she later used the forenames Hannah Lucy. There is a 1971 death in Peterborough district of Hannah Lucy Kennelly in 1971 with date of birth 13 Aug 1894.
Several trees on Ancestry have her starting life as Hannah Lucy Hazell in Reddish Lancashire in 1894 but I can't work out how, if that's her, she came to have the surname Markson.
If I'm right that your Gordon Roland Markerson/Markinson is actually Gilbert Richard Pitchers then the 1934 marriage to Phyllis was likely bigamous too! He seems to have kept his initials and created a surname based on the maiden name of his wife!
My curiosity got the better of me and I sent for Richard Gilbert Pitcher's birth certificate. I had to use the reference from freebmd as I couldn't seem to find the same one on the GRO index.
The PDF arrived today and guess what? His date of birth is Ninth December 1901. BINGO!!!
I'll try and snip part of the cert. What does everyone think? Is it case solved or have I lost the plot?
Best wishes, Tony.