FID SG Z104 PORT FOSTER 5s deep rose-red on piece RARE

1913 piece addressed to Punta Arenas Chile with Falkland Is 1912-20 5s deep rose-red (lifted and hinged in place) tied by fine complete strike of PORT FOSTER straight-line handstamp (Deception Island South Shetlands) and by FALKLAND/ISLANDS type F4E cds dated MR 31 13. RPS Cert states Philatelic. There is one slightly toned perf a Major a Rarity. The only example we have ever seen. BPA cert (1971) Heijtz PF.1a priced at 700 pounds Ex Stanley (Spink 4/3/98 lot 602 sold for 400 pounds)