Cloth Seal, Belgian, Ghent, Fleece, Lion, Image by StuE, Found by Barney Rubble.
Found in the Essex/Suffolk/Hertfordshire area, 18mm, 5.0g.
A double disc cloth seal showing a fleece (sheep suspended from its middle) and on the other side a lion rampant possibly with the letter G beneath.
This is a cloth seal from the city of Ghent in Belgium. Another example with a different reverse can be seen on this Dutch forum and the next page looks to have a matching seal that may well have the missing parts of the image on the reverse.
The suspended sheep represents a woollen fleece signifying the woollen cloth trade.