Starboard
Port
Larry,
5 over 6.....6 over 5?
I have swayed backward and forward on this for a couple of hours.
Some elements suggest one, other elements the other. Clearly side to side variation over 50 plus years of exposure to the elements is evident as is, to some extent, the angle of attack to the sun due to the fuselage curvature.
There seems to be a chemical etching effect on the base finish as seen with the 8 and that has started to appear on the upper half of the 6 on the starboard side. These etch or witness marks reveal the true stroke dimension of the numerals, wider than you might first interpret due to the single paint thickness white outline being almost totally eroded.
I have made the assumption that both the 5 & 6 numerals have been painted on as firstly a coat of white at full dimension followed by a coat of black at under dimension to give a 10-15mm white border.
The puzzle, if the 6 was the last applied numeral, is why there should be quite that amount black in the area of the pink arrow, an area than can only be part of the 6. The visible white in this area has been protected by the black before eventually showing through. The unprotected border white in this area has totally eroded by virtue of the known stroke width.
If we consider the top half of the 5 in the port view, the area I have dotted with bright green spots. I believe we are seeing strong black here because the 5 has been locally protected by two coats of the radial stroke of the 6, yet has faded on the outer elements of the top horizontal, where it has not protected by the 6.
I believe in the port view that the last vestiges of white radial stroke from the 6 on the strong vertical black of the 5 could only mean that the 6 was applied over the 5.
So Larry, a cautionary 'Black 6' when it fell into British hands and confirming your reports.
Peter