Yes I`ve found it, and funny enough I was there not long ago.
There is a lane up the side of the Red Lion ( now called Frwdd Inn ), up there is a little Parkland with a small lake. Carry on along the path across the field , there is an open coal face ,and you come to Cymau.
I remember when I was little , the families from Gwersyllt used to go for a walk on a Sunday over the border into Flints. As soon as you crossed the Alyn in Cefnybedd you could have a drink.

A treat was a bag of crisps and bottle of pop.