His Tempest wasn't finished in High Speed Silver which was introduced in 1949, consisting of a multi part finish, a pigmented synthetic resin applied directly to the metal, a filler, then a finishing coat which was polished twice, first with a cutting compound followed by a liquid polish. It is a common mistake to equate High Speed Silver with the aluminium dope that had been applied to British aircraft from pre-war years. It is one of those errors which is constantly reinforced by repetition, as in the video above. It is a "complex story", but has nothing to do with High Speed Silver.
His post war Tempest was finished in an earlier aluminium coloured scheme which was deemed unsuitable for high speed aircraft, really meaning jets, hence the introduction of the new scheme in 1949.
I'm not sure that the aluminium finish was applied over the original camouflage either, but I could be wrong.
Cheers
Steve