Hello Tall Al,
Your ancestors were of interest as I have ancestors from Llandudno and my grandparents are buried in St Tudno's too. I know the Old Telegraph House that you refer to. I better stop reminiscing about Llandudno or I'll be here all day!
The Parish Registers for Caerhun (another lovely place) are on Freereg.
http://www.freereg.org.ukI looked for a John Williams there and found quite a few entries for baptisms of this name in that period. They have the following:
2x baptisms for John Williams in 1817.
1 baptism for john Williams in 1818.
1 baptism for John Williams in 1819.
1 baptism for John Williams in 1824.
There are more in other years but a bit further away from 1821.
The father's name of Thomas Williams narrows the search down a bit and the ones with Thomas as their father are:
John Williams, baptised 02/02/1817 Caerhun Parish Church, son of Thomas Williams and Emma.
John Williams baptised 04/07/1819, son of Thomas Williams and Jane.
I cannot seem to find any siblings for either of them.
The marriage could not be found for either couple but it doesn't look as if the registers for Caerhun are on Freereg.
Can anyone find him on the 1841 to see if he is married then?
Since the name of John Williams is so common in North Wales, you may be in difficulty finding him and his first marriage.
Jo.