PL.3 (OI) CONSTANT VARIETY (SG21 SPEC C4g) ON COVER. Fine envelope (inter banking) Warrington to "Sheffield and Rotherham Bank Bakewell" with a good used die 2 1d pl.3 lettered OI S.C.16 (SG21) tied fair strike of the Warrington spoon original type MY 26 1855. Light fold affects stamp BUT stamp fortunately centred low and thereby shows superb CONSTANT VARIETY "MARKS BETWEEN NI/OI". Inner flap references payment between banks. Excellent usage from this scarce plate. (Ref 107411).