Cloth Seal, London Dyers Company Seal, Swan, Image by Karen Ellis-Andrews, Found by Roy Ellis.
Found on Thames Foreshore, 20mm.
Swan // madderbag, I above
The madderbag is a symbol used by the London Dyers' Company (I above indicates one wash in the woad to give plunket, a light blue, a second wash gives azure and a third blue, see p.199, Elton, S., Cloth Seals, An Illustrated Reference Guide to the Identification of Lead Seals Attached to Cloth: from the British Perspective). The swan is most probably a reference to Old Swan Lane on the central London waterfront area where the guild set up its work places.