Cloth Seal, Alnage/Subsidy for Faulty Cloths, Image & Found by John GM.
Found on the Thames foreshore.
See UKDFD Ref. No. - 33741
"One disc only of a two-disc alnage seal for faulty cloth. The seal bears a large letter F dividing the letters GI and surmounted by two small crowns. The crowns are each over a small letter, possibly H. The design is encircled by an inscription between inner and outer circles, but damage to the edge of the seal has removed part of it. The surviving part reads SIGLLVM: GLOS[ET]ER: [ ]: (note that 'I' is missing from SIGILLVM).
It seems likely that the full inscription would indicate that it is a seal of the county of Gloucestershire, and the letters GI may relate to the inspectorate of that county. The small crowned letters are probably the cypher of either Henry VII or Henry VIII."
Endrei, W. and Egan, G. 1982. ‘The sealing of cloth in Europe, with special reference to the English evidence’, Textile History, 13, 47-75:- "Not all the cloths sealed by the searchers had fully satisfied the requirements of the assize. Under Edward IV seals were to be put on faulty cloths and in the middle of the 16th century a seal stamped with the letter 'F' was specified for those with imperfections in the finishing. A statute passed a few years later required the use of a seal reading 'faultie' in full. May, writing in 1613, mentions the cutting of a notch in the edge of the cloth beside each defect, and the fixing of a seal in this cut to advertise the fault to the buyer. Cloths which were seriously defective were marketed as remnants with the lists torn off. A Suffolk seal with a letter 'F', one from Yorkshire reading 'falty', and two which are not inscribed with their provenance, but which were probably attached to Norwich worsteds, reading 'defective' and 'to[0]shorte' respectively have all been found in London, showing that pieces known to be imperfect were traded over considerable distances."
Circumstantial evidence has been found for the careful removal of this type of seal, no doubt to replace them with ordinary alnage seals to get the better price of a fully compliant cloth, see p.278, Carter, T., Egan, G. and Medlycott, M., Cloth seals and other metal-detecting finds from Saffron Walden, Essex Archaeology and History, vol.33, 2002.