Swaziland 1894 ½d Official Re-Issues, Stop in Overprint

1894 Official Re-issues of the 1889 issue WITH STOP AFTER "SWAZILAND": ½d grey perf 12½, WITH INVERTED OVERPRINT, two copies showing respectively round and square stops; Superb M. An exceedingly rare pair of which apparently only a single sheet with the inverted overprints was prepared. Photo-cert & Signed: Holcombe. Ex Roth. See additional image and of certificate below.