BARBADOES dbl-arc postmark/cancel on DOMINICA stamp arrival dated AU 19 1877 on Dominica QV 6d green CC wmk (SG.8) being the UPU to non-UPU 6d inter-island rate. Dominica joined the UPU JY 1 1879, Barbados joined the UPU SP 1 1881. £90
UPU MALTA to non-UPU Melbourne, VICTORIA, Australia postal history 1890 opened to display cover showing HUDDART, PARKER & Cos.. LINE printed sender's flap to Huddart-Parker & Co, Melbourne, Australia with QV 4d brown pmk'd Malta "A25" duplex dated H/SP 11 90, b/stamped Brindisi (13-9) and Melbourne (OC 16). Malta joined the UPU on JY 1 1875 but Australia did not become a member until OC 1 1891. £180