A Grade II listed sundial (base) in the western most corner of the gardens of Lauderdale House, Waterlow Park, Highgate, London.
Based on a 2017 photo by Charles Watson on the Historic England listing, the sundial now seems to be missing its top.
Interestingly it had a plaque that was inscribed: "This dial plate is on a level with the top of the dome of St. Paul's Cathedral".
https://historicengland.org.uk/listing/the-list/list-entry/1379132
151 photos taken in August 2022 with a Sony a7R III and processed in Reality Capture.