Hi,
I've received the certificates and there is good and bad news. The bad is that the birth certificate for Festiniog June 1863 gives the father's name as Owen Jones (again). The good is that the marriage certificate definitely looks to be right. The details are as follows....
29 March 1864 at Register Office in Festiniog.
James Jones, age 24, Bachelor, Tailor (Journeyman), Residence- Portmadoc Ynyscynhaiarn,father James Jones (deceased) Cabinet Maker (Journeyman).
Jane Hatcher, age 23, Spinster, Domestic servant, Residence- Aberia Llanifihangely Traethau, (note, the writing is very small so I may have misread),father William Hatcher, Farmer.
The registrar signed James's & Jane's names. The witnesses signed their own names- Owen Walter Evans & Anne James.
Thank you for your help, Gary.