Hi,
Benhall and Saxmundham are very close to each other so highly likely they arethe same people and its a true link.
Kriywan - I am still hoping to find a link re John for you but havent stumbled across anything yet - seems theres a few others on here looking for same links!
The birth marriage & death index has this info
Marriages Dec 1892 say  
Bloomfield Esther Maria     
Cotton    James Samuel    
Plomesgate    4a   1857   
Plomesgate is Benhall - if you go to the General Records Office on line and put in the 4a (volume) and 1857 (pge) and pay them £7 the certificate will come abck which may give you leads as to the paretns and locations.
The 1901 census says that James was born in Yoxford
and his fmily members are
James S Cotton     39, Ester M Cotton    40, Emma E Cotton    7, Ester J Cotton    5, James R Cotton    3
if the father  was 39 then his birth date was 1862 give or take - they seem to be living with a lot of other people at 70 High st Saxmundham
ah James was an inkeeper - that will explain the lot of household members he has - they were all lodgers.
James Roberts birth comes up as...
Born in Dec 1897  
Cotton    James Robert       
Plomesgate    4a   (vol) 962 (page)
If you are going backwards then James Samuel appears in the 1881 census as living in Yoxford with his parents Emma and John R as a carpenter apprentice with siblings - father born Stowmarket and in the 1871 census again the family appears complete with his siblings in Yoxford his father is listed here as a harness maker.
I can not find any marriage for James Robert only a death mentioned above.
However the debate still rests on whether you are tracing back or forward and how much info you already have. 
If you can let us know we can all have a dig about a bit more for you.
Yi