UPDATE
OK I ordered up the Pentir non-dom MIs. Thomas & Jane Williams are not on there

As a matter of interest for anyone else looking the burials all seem to be from the 20th century)
I did manage to find Thomas Williams, widower, at Cefn Braich in Rhiwlas in 1871 age 73 but gone by 1881.
I checked the Macpellah site Sharon but no luck there
If anyone has the MIs for Llanddeiniolen itself I would appreciate a look through there. Ive not been able to find a marriage for them in the Arfon marriages between when Jane's first husband John Roberts died in 1835 and mid 1837. The registrar at Caernarfon says there is no marriage after 1837 so I'm beginning to think they never did marry

. Perhaps that is why they are not buried at Pentir which would be the logical place. That being the case, it is possible that Jane is buried as Jane Roberts and not Williams

Any and all suggestions considered

Thanks
Heather