At last, I now have the marriage certificate for the Robert Jones/Margaret Roberts marriage in 1854.
The date is the 4th January, 1854 at the Independant Church (?? Street, Llanrhydd ??).
Robert is a husbandman, residence Garthinen, Llanelidan, and his father is David Jones, farmer.
Margaret is a servant, residence Bodlwydd Ucha, and her father is John Roberts, shoemaker.
In later censuses Margaret says she's from Llandderfel. I scanned the Llandderfel census and there seem to be a number of shoemakers there so maybe it was a local industry ?
I tried to find 'Garthinen' as a residence on the censuses, but couldn't locate it, certainly not in Llanelidan, so I've no idea where it is. I think I've got the spelling correct so maybe someone else may have some insight ?
This does look like the right marriage for my family. Brynhyfryd was a row of cottages quite near Bodlwydd Ucha, and Robert Jones my g-g-grandfather was born in 1854 soon after this marriage so it all seems to add up.
Thoughts anyone ?

Thanks, Gordon.