Re the 1860 Halfpenny.....very simply, in 1860 a radically new style and type of Penny/Halfpenny and Farthing were issued for circulation....these were now made in 'bronze' and were far smaller,lighter than the Pennies/Halfpennies and farthings that had previously circulated until then, which had been much larger, heavier and had been made of copper.....a couple of shillings worth in your trousers and you would have walked with a limp. Only a handful of the older style copper pennies/halfpennies and farthings were dated 1860....and they were in fact coins dated 1859 that had had their dies recut to 1860...it's these that are extremely rare and to which you were refering to. They are also known in gold...I have an 1860 farthing in gold.