Hi Laurence
Not sure if you already have this information.... sorry if you do....
I found John F C CLARKE in the UK Census 1851 - 1871.
In 1851 he was at school in Campsall Yorkshire in Bournsdale Summer House. Aged 14, a scholar, his birthplace given as Carlton Yorkshire.
In 1861 he was living with his mother Ann in 8 Pontefract Road Court # 3. Ann was described as Married, a Proprietor of Houses, and John F C was a Maltser, employing one man.
1871 he was living Keresforth Hill, Barnsley, but now he is a farmer of 118 Acres employing 2 labourers. His mother Ann is still with him but now listed as being a widow.
If you would like complete transcriptions of these 3 census, I would be happy to do it for you
Cheers
Karenlee
ADDED In 1881 John still with Ann in Barnsley, 14 Churchfield, now a commission agent. 1891 he and Ann in 58 Sackville Street, a Commission Agent for Coal and Timber.