Hi Roger
Thank you very much for your inputs which have made me have a re-think. Answering your points in reverse order:
No I have no details of William's siblings, however, there is one avenue which I now need to investigate which I will explain later.
I believe there is a slight transcribe error in BMD. The next marriage entry in St Cawdraf's Marriage Register taken from Yffor.com is:-
71 05/09/1843 Watkin Williams FA Ba Grocer Tynllan Llanarmon Wm Rbts Fa Anne Jones FA Sp Fourcrosses Harry Jones Gr
William Williams should be Watkin Williams a grocer who married a different Anne Jones.
It is frustrating that I cannot find the original register image on Findmypast who really messed up the filing of Welsh Parish Records some years ago. If you search for the an Ann Jones married in Abererch the records submitted are for Beddgelert likewise Ynyschyhaiarn are under Tudweliog and Clynnog under Capel Curig. End of my moan of the day but the original image may give the names of witnesses which could be a clue.
I must apologise for putting copy and paste lines from Yffor.com without headings which has probably led to some confusion since Thomas Williams was not a joiner but a labourer (Lab). The joiner was the father of Anne Jones, Griffith Jones (Gth Jones). However, writing Griffith's name out in full has suddenly made me realise that like many other Welsh families there seems to be a tradition in my family of naming the older children after their grandparents. Thomas and Anne's son (my Father's Grandfather) was named Griffith as was my Father who was named Griffith Richard after both his Grandfathers.
Thomas and Ann's children were named as follows:-
Elizabeth (1843-1846), Jane (1845-1857), Elizabeth (1848- ), Griffith (1850-1922), Catherine (1857- ) and Jane (1860-1831). It my be significant that after the early deaths of the first two daughters they had to use the names for subsequent daughters. I believe Jane was named after her maternal grandmother and Catherine after Anne's Grandmother. Elizabeth is the one I cannot connect, could she be named after Thomas Williams wife? Griffith Thomas's eldest daughter was also named Elizabeth.
Glyn