Australia-South Australia-A Queen Victoria 4 Pence (plum) Postage stamp with "Official" Overprint-Illustrated

Illustrated below is the 4 Pence (plum) postage stamp issued for South Australia between 1876 and 1885. The stamp was overprinted for official use in 1881. Many of the stamps issued in South Australia during the 1870's and 80's have a variety of colour variations and perforations that can make the stamps difficult to classify. Many have minor and sometimes hard to determine compound perforations. Two varieties of watermark appear on the stamps of these years a "large star" and a "broad star". The watermarks are also quite close in appearance.
The example shown here has a perforation of 10 x 11and a half with a broad star watermark. The watermark is illustrated below the illustration of the stamp face.