Just been looking at your response again and I did think it could possibly be him but now I'm not so sure. Here are results of my research so far:
My Grandfather was Stanley Hubbard. His Father was Frank Hubbard whom I have found on the 1911 census:
HUBBARD, Frank, Head, Married, M, 52, 1859, Lincensed Victualler Out Of Work, Northampton, Kings Cliffe
HUBBARD, Sarah Jane, Wife, Married 28 years, F, 45, 1866 , Norfolk Snettisham
HUBBARD, Harold, Son, Single, M, 20, 1891, Clerk To Coal Merchant, Lincoln, Spalding
HUBBARD, Cecil, Son, Single, M, 14, 1897, Erand Boy School, Lincoln, Spalding
HUBBARD, Elsie, Daughter, Single, F, 11, 1900, School, Lincoln, Spalding
HUBBARD, Stanley, Son, Single, M, 9, 1902, School, Lincoln, Spalding
Subsequently through census I found Frank's father to be James Valentine Hubbard.
I then found James Valentine's marriage and have the certificate:
On 26 May 1844 marriage solemnized at The Parish Church in the Parish of St. Gregory in the City of Norwich.
James Valentine Hubbard, Bachelor, Tailor, residing at time of marriage in St. Gregory. Father James Hubbard, Tailor.
Sarah Johnson, Spinster, residing at time of marriage in St. Gregory. Father William Johnson, Bricklayer.
Married by William Hun PC in the presence of Samuel Scott and Susan Scott.
That is how I came by the name James Hubbard. Although James Valentine is listed as a Tailor at the time of his marriage on all subsequent census he is listed as a farmer or gamekeeper. The census places his birth around 1820 in Great Melton, Norfolk but I cannot find any birth record. The only clue I have as to his parents is from the marriage certificate, ie Father James Hubbard, tailor. If family legend is correct regarding the French POW then I imagine that this would be James Hubbard. Unless my calculations are incorrect and I should be going back another generation to look for the Frenchman?!!
The only birth record I can find that could be a match for James Valentine is to parents James Hubbard and Pleasance Fisher but that James was born in 1786 in Melton, Norfolk, not in France or 'Foreign Parts' so although the census records fit, I don't think that's him. He is also a farmer.
I'm struggling with the National Archives and can't get to Kew and am completely stuck, going round and round in circles so if you can help in any way that would be fantastic!