1937 Coronation Registered Cover to Canada, dated 6th August 1931, over 5 years before day of Issue

6th August 1931 Registered Cover to Canada, with Newman Street Hooded Registered cds, back-stamped Montreal & Charlotte Town Canada 19 / 20th August 1941, ten years later. The 1½d Coronation stamp was issued on 13th May 1937, some 5 years later than the postmark. Passed by Censor PER94 cachet & Oval British Philatelic Association Cachet, authenticate the cover as genuine. Very unusual cover, in Pristine Condition, sealed with no contents.