Cloth Seal, German, Cologne, Image & Found by Mark Iglesias.
Found on the Thames foreshore, ?mm, 3.5g.
Shield bearing three crowns in chief crosshatching below // possibly the same with only two crowns
These are the arms of Cologne, Germany.
For a parallel see Euro Plombs, "The 11 ermine tails on the city's coat of arms are not visible here. We can therefore deduce that this lead dates from a period prior to their appearance (circa 1500)."
Another is shown as no.8 Fig.1 in Mordovin, M., 2018, A Collection of Fifteenth- and Sixteenth-Century Cloth Seals from Szolnok. p.285 GENIUS LOCI LASZLOVSZKY 60, edited by Dóra Mérai and Ágnes Drosztmér, Kyra Lyublyanovics, Judith Rasson, Zsuzsanna Papp Reed, András Vadas, Csilla Zatykó, Budapest 2018. This also dates the seal to the late fifteenth or early sixteenth century.
For a different style of Cologne seal see BSG.CS.00113.