UK and Europe Roadtrip - Clumber Lake

Looking across Clumber Lake there is a 'folly' that is fashioned after a Greek Doric Temple. There are a number of walking or cycling trails around the 1500 hectares of Clumber's wooded parkland but I haven't seen one that takes you to the 'folly'. A small chain ferry used to be used to cross this lake when the Duke lived here.