This High-speed silver finish appeared 1948-1949.
The finish was officially named “Silver Dope” – to spec. 33B/317 516. Type C – Cellulose; a mix of 4-1 aluminium/clear dope.
The slightly later finish was: “Colour Silver. Spec. Cellulose DTD 63 Synthetic DTD260 Stors Ref Cellulose 33B/317, 556, Synthetic 158, 561.”
Both had a nasty habit of fading/weathering rapidly; and when polyurethane paints arrived, there was no metallic version…. so they went for Light Aircraft Grey.