BRIDOL is the British Sundial Society's Register of Fixed and Mass Dials, which gives detail and photographs of about 8000 fixed sundials and 3000 mass dials in the UK.
Some of these are in private gardens, but the majority are publicly available.
This mansion is deceptive: even the stone bearing the date 1620 was imported from another building and much of what you see today is what Pevsner describes as "an intriguing confection by Sabine Baring-Gould". We may wonder whether the sundial over the front porch started its life elsewhere too. It is apparently old and has been dated to 1696 but the hour markings are faint and difficult to read. An attempt at some time to restore it has resulted in the gnomon being fixed so that it points upwards. It is thought to be of slate and measures about 600mm square. A good phoro and more research needed!