Zanzibar 1895 QV 5r Tall Second Z with Antique R in Block

1895-96 QV 5r ultramarine & violet "TALL SECOND "Z" in combination with ANTIQUE "R" (SG 21Cvar). Suberb M/UM block of four with the variety on top left stamp. Possible marginal watermark guideline on top right stamp suggests the block may be plateable to positions r1-2/3-4 of one of the 4x3 settings. A rare & attractive multiple. (cv£450+). See additional image.