Cape of Good Hope 1856 1d Triangle Early Soldier's Letter, Rare

1856 SOLDIER'S ENTIRE LETTER to England franked 1d pale brick-red Triangular, blued paper (SG 1). A fine early example of triangular franking for the PENNY CONCESSIONARY RATE. Sender was "No1758 Pte Wm Moores, 6th Royal Regt." and the letter inside is headed "Line Drift 21st May 1856". Bears required endorsements and Officer's countersignature for this military concessionary rate. Adhesive has strong colour, neatly cancelled, clear to full margins, corner defect (cracked/torn/repositioned at extremity) at bottom left. Relevant backstamps include origin at Grahamstown with oval ds MY 27. A rare cover.