"The Spitfire Story", Alfred Price/Arms and Armour, page 36 shows a document, prepared for the board of directors of Vickers, outlining the costs of building the "Modified Single-Seater K.5054".
This was presented at the board meeting that took place on 2nd April 1936. Against the heading "Expenditure to first flight" was the note "not yet flown", but beside it , in the hand writing of the Company secretary Henry Duvall, "Flew 5 Mar 36".
Ciarain.