Hi Zoe,
It would be a great help if you could put up a list of names, places, ages and dates that you know. That will help us all search if there is a possible transcription error that is hiding the information you seek. For instance, this is what I have from what you have wrote:
Henry Andrew Hawkins married Rosa Twyman before or about 1870
Henry and Rosa were from Strood, Kent
Henry and Rosa had a son, James Hawkins born Dec 1870.
Henry Andrew Hawkins died about 1883. Occupation: Engine Driver.
James Hawkins worked on the sea (Hall Porter) after his fathers death
James moved to Sheffield in 1917 after marriage (Certificate obtained)
Questions:
Do you know Henry or Rosa's birth year or approx. age?
Do you know if they used other names? Henry aka Harry? Rosa aka Rosina?
Do you know if they were born in Strood Kent?
Do you know of any family connections - Parents or Siblings of Henry or Rosa?
Do you know where and when Henry died?
Was James an only child?
Where was James born?
How do you know James occupation? Marriage Cert. or from your Nan?
If you could go over all the life evens and just fill in the Who, What, Where, When and How it would be of great assistance.
By the way, have you checked out the following census:
1881: RG11/1247, Folio 59, Page 5 - Henry Andrew Hawkins age 44
1891: RG12/951, Folio 100, Page 23 - Henry A Hawkins age 54
The information doesn't match what you have provided but it will help if you could rule this family out.
I hope this is of some assistance,
Nancy