Variations In Official Overprints on Early South Australian Queen Victoria Postage Stamps

Some examples of the varieties of official overprints on early South Australian Queen Victoria stamps are illustrated below.

The bold OS is the earliest  version of the overprint and dates from the 1860's, the next  a finer lettering from the the 1890's and the widely spaced variety from the early 1900's. Many must have been stamped by hand as the variation in position shows in the final example.