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.
No markings visible on stonework, but the remains of an iron gnomon. Above is a lead flashing strip, possibly protection for a dial plate. Located on the SW face of the SW diagonal tower buttress.