Update. These die transfer coins are much wider than any of us expected. Echidna was ripped off, I've been ripped off, CoinOS has been ripped off (explanation on your 1911 shilling thread). So the known fakes include the 1911 and 1936 penny, the 1923 threepence and the 1911, 1914, 1916 and 1925 shillings. These are just the ones I've confirmed but probably other dates/denominations out there.