Dear Ironhorse, many thanks for your response. I think your lateral thinking is pretty much spot on. If you look at the counmarked side you can see rough sections at 3 o'clock and 9 o'clock, where sections of metal have been snapped off (originally I thought these were just roughness at the edge), which leads me to suspect that this "coin" originally actually part of an official security band of some sort. Might have passed as an unofficial token in one of the poorer parts of the empire (came to me in a box of worn Indian Victorian coins), just as worn flattened buttons are known to have circulated in Ireland as tokens during the coinage shortage at the end of the 18th century. Anyw mystys solved. Once again, many thanks.