Sunday mornings in Hayle, Cornwall there is a regular car boot sale on the Rugby ground. We like Cornwall and go most years. When it isn't raining we will usually visit the car book on the way to somewhere else. In August 2016 we visited the car boot and as usual bought a few bits of bric-a-brac. On the way out I passed a stall that I had not seen earlier and this jug was sat on the paste table among other random stuff. I like Doulton saltglaze and was drawn to the strange design applied to the front, it reminded me of the symbol of the singer formally known as Prince. It dates to the early part of the 20th century and is in great condition. I negotiated a £10 discount for cash and walked off with it.
Internet enquiries show that the symbol is the merchant symbol of William Swayne of Salisbury and is found in a stained glass window at St Thomas's Church where he funded the construction of the Lady Chapel (a.k.a. Swayne Chapel) around 1457.