Bahamas SG149eb KGVI 1/2d brown-purple BLOCK St Edwards Crown ERROR in the Wmk

Bahamas SG149eb KGVI 1952 1/2d brown-purple BLOCK of FOUR with NASSAU CDS of 10 MAY 61 (When the stamps were still Valid). Top right stamp shows the majority (80%) of the St Edwards Crown ERROR in the watermark. Excellent Colour. A Very RARE Multiple. SG cat 3250 pounds as single stamp. Ex Charles Freeland