Good evening,
These were two seperate chapels, one in bridge st and one in the high st as KG said in reply 1.
The Ynysgau chapel in bridge st was demolished in 1966.
The Zoar chapel in the high st is still there, it is a listed building.
If you look at the site " churches of England and Ireland". Go to Methyr Tydfil and scroll down to Zoar chapel you will see a picture of it. Although on the high st it is up a gated alley so can't be seen very well on st view.
When I can get on the laptop later I will put up some links of both chapels. There are pictures of both available online.
John915