Description
GB DL size envelope with Postal Strike label inscribed ‘R.& R.S. G.P.C. approved Special Post Feb 1971’, 1/-(?) crossed out and 10p added (during the current currency change), black on pale yellow, cancelled by h/s ‘Research & Recruitment Services, 132 Great Portland Street, London W1’ 26 Feb 1971, to London EC2: seems as genuine as any are