cover 1921 (10 Jan.) envelope (opened-out) annotated "Registered Insured #1.10.0" to Groves & Lindley, England, bearing, on reverse, ½a. (2) + 1a. (4) tied by two strikes of segmented c.d.s. (D1.) with London registered d.s. in red adjacent and bearing, on front, "INSURED" label in pink and blank registration label. Extremely rare. Photo