Cliefden currently has access issues, and is not currently being visited by NUCC. This is a shame, because the caves there are fantastic! It has lots of caves and they totally don’t deserve to be drowned under a dam!
NUCC's own page for Cliefden is this short, for the reason it gives above — the area isn't currently being visited, so there's no "getting there" or driving-time information to show here.