The Rare UHB Roll 12S V6 mint variety "Grey spot near tip of first sunray". See below.

The Union Handbook of 1986 (S.J. Hagger) page 133, states that "In their roll form, these stamps are extremely rare, in fact the rarest of all the Union's roll stamps"

The parts of the web which were not required for making into rolls were guillotined into sheets, and sold over the counter. These R12S stamps are also rare, and the variety below, from the Wolmarans/Hagger collection, is a rare example of one of the Multipositive varieties - V6 - "Grey spot near tip of first sunray".

With hinge remainder as per scans below.