MARINER mentioned the Ar Log albums - the ones I have are on the Dingle's label and are:-

DIN 305 - Ar Log (1978)
DIN 310 - Ar Log II (1980)
DID 715 - Ar Log Meillionen (The Clover) 1982

all on vinyl and I would expect no longer available.

I also have GVR 215 (Greenwich Village) Tonnau Gwerin but the quality leaves a lot to be desired.

I was born in Bryngwran, Sir Fon so I qualify as half Welsh at least!

Bob vG