Gwen ......... don't panic!
I had another look at Robert with his mum on the 1891 census because I wasn't sure of her birthplace and thus had another idea .......... it looked more like Westbury (I've changed the original posting to that effect) thus ..............
I think that I've got it right this time
1871 .............. the writing on the census is VERY difficult to read but .................
25 C.................... Street, Roath
John GIBBS head mar 52 labourer b.Glos Halle??
Mary Ann wife 50 b.Glos Westbury on Trym
Elz?? Ann dau 20 b.Glos Westbury on Trym
John son 2 b.Glos Westbury on Trym
Clara? .......... GIBBS dau 3m b.Cardiff
John EDWARDS boarder 21 labourer b.Glos Westbury on Trym
Henry MANSFIELD boarder 28 labourer b.Glos Durdham Downs
RG10/5367 folio 46 page 44
Somebody who is familiar with Roath or Welsh names may have some idea what the street is called. The wording Great Eastern Inn (on reflection it may be Terrace) has been crossed out - this is the same wording as on the other GIBBS in the 1871 census.
Henry wasn't indexed as MANSFIELD - the "s" had been left out. I think that Elz Ann is quite likely your Elizabeth Susan and possibly her husband to be Henry MANSFIELD
That looks better doesn't it?
Casalguidi