Unable to answer "What are the opening hours here?" – Roundstone Farm Shop (Produce Stand) – https://osm.org/way/981000548 via StreetComplete_ee 63.0:

It appears the gate leading into the car park for Roundstone Farm has been closed. The sign on it mentions something about "It's time to step down" alongside 'CLOSED' in red letters. I don't know if this means the buildings inside the perimeter are closed but probably? Only seen the sign while driving.