The hall doesn’t have a postbox, or postal address as such, but its address could be described as:

Neuadd Goffa
Mynydd Llandygai
LL57 4LQ

Below is a Google Maps aerial photo showing the location of the village hall. There is a small car park opposite and cars can be parked along the road.

View Neuadd Goffa location in a larger map

Here is a Bing map showing Mynydd Llandegai.