The 1859/8 overdate half sovereign is one of the lesser known overdates despite the clarity of the 9 over the 8. This is likely due to its scarcity rather than anything else giving it the potential to be one of the series sleeper dates. An example sold in Heritage in 2012 for US$10,925 (Heritage Auctions, 2012) - a price not more than the value of a normal 1859 indicating that at the time, the market had not fully appreciated the variety. This example had been certified by NGC at MS61 without the overdate attributed on the holder.
The illustrated example however sold in Nobles in 2009 (Noble, J, 2009) , graded nearly very fine/very fine well beyond the price of a normal 1859 in that grade indicating that perhaps its popularity just had not spread out of Australia at the time with Heritage being a US based auction house.