Don’t worry about the discolouration of your print. At least the signature was in pencil. Some weren’t and have suffered the same kind of fading as the print.

You’re not wrong Kev. I’ve seen one RT print from the same era, which IIRC was signed by Galland and either Bader or Johnson. Sadly they must have been in ink, as nearly 30 years later, hanging in an RAF office, there was almost no trace of either signature.