I just happen to have a copy of P & B Withers book "British Coin-Weights A Corpus of the Coin-Weights made for use in England, Scotland and Ireland" in my possession (I borrowed it from a fellow numismatist). It lists over 2,000 coin weights, which were made and used in the British Isles for British and non-British coins. A quick review shows that none were as crude as your piece.