The Shield reverse, Young Head series was struck from 1871 to 1887 at the Sydney and Melbourne mints. Both mints went through a number of different reverse and obversevarieties during this period making for one of the more interesting series and all dates are reasonably affordable in low grades though some such as the 1885 Melbourne, coming from a tiny 11,000 mintage are very scarce in any grade. When considering varieties however, the key date is the 1881 Sydney crenulated reverse type which is known by only a handful of examples and was unlisted by Marsh(Marsh, M. A., 2004). Marsh however lists an 1882 Sydney for this type though no examples have surfaced on the open market. It is likely that this issue was struck but in very small numbers. Considering that the survival rate of the era is about 5%, if they were struck in small numbers, it is likely that very few or none have survived.
In top grades however the Young Head series is very difficult with many dates just not having any surviving examples in mint state. The higher survival rate in high grade of the Sydney mint series is more likely to do with the design being different, and uniquely Australian at the time that the pieces were often hoarded after the introduction of the Imperial design.
The reverse features the Imperial shield design with the legend BRITANNIARUM REGINA FID DEF while the obverse features the Young Head effigy of Queen Victoria with the legend VICTORIA DEI GRATIA with the date at the bottom of the coin. The mint can be determined by either an S or M mintmark underneath the shield on the reverse. The absence of a mintmark or the presence of a die number indicates the piece was struck at the Royal mint in London.