Cloth Seal, Tubular, XXXIIII, Image & Found by Mark Iglesias.
Found on Thames Foreshore, 25 x 19mm, 6.2g.
XXXIIII in knotted rectangular border // plant?
The X's each have a distinct 'S' curved cross stroke.
A tubular or 'pipe' cloth seal. It is difficult to know whether this is an English or Continental seal as tubular seals with Roman numerals were used in several places. See BSG.CS.01661 and BSG.CS.00998
The distinctive S-curve on the X's can be seen on tubular seals from Leiden, see cat. no. 31, Oostveen, Textiel_loden gedateerd rondom 1650-1665, 2016.