Masyronnen is a chapel up in the hills north of Glasbury, it is one of the first Chapels in he area. 1691 is the date believed to have been it beginning in a farmhouse
They are not down as baptised at St Peter's Church in Glasbury either.
But churches wre often out of repair and other churches were used.
It might be worth getting the birth certificates from Hay register office to see where David number 2 was born.
Hay Register Office
Broad Street
Hay on Wye HR3 5BX
There is a David Price son of Ann baptised in 1841 in HAy but the only one I can see locally.
The border between Radnorshire and Breconshire is no help here either ! HAve you tried Powys Family History Society ? They have a website.