Dominica SG 26 Unmounted mint 1886-90 1s dull magenta watermark Crown CA block of 4

1886-90 1s dull magenta, wmk CA, left marginal block of 4, unmounted o.g. Fractionally yellowish gum, still fine fresh appearance. A rare multiple. (cat £1000+) [N.B. Only 1200 stamps (= 20 sheets) were printed, of which 774 were remaindered. Only four blocks of 4 (incl a plate block) are believed to survive in private hands, plus a further block in the Royal Collection.] - P256001148