Hey Chris,
I got the scans you emailed, I'm home for lunch and see that Leon's already posted it.
The front borders look very white. When looking at the back of Duffy, the one on the right, the borders look wobbly, not straight. If he's loose I'd soak him one time, for 2 reasons. 1- some of that non-original residue might release, thereby unaltering the card. 2- if someone did bleach it a bit, a soaking overnight would help to dilute any remaining chemicals, making them less likely to affect the card in years to come.
I'm posting the front scan you sent so folks can see that a bit of the image on the front of Duffy is gone, especially in the top right. That could be from a bit of bleaching, or it could be from other causes. Also, Foxen is a name I recognize from series 2 of those great Old Mill red border cards...
Frank W.