In reply to timmyhobby:
I've only been once so a local will know better. I reckon both sugar magnolia and tydomin will be cut off by the tide by 2 hours before high tide, and probably by 2.5 before.
The walk in from the north will be cut off by mid tide, maybe slightly earlier however its possible to walk south from the crag along the beach and up a path in the cliff which offers a far less tidal way in / out (probably sufficient to allow climbing close to high tide).