Those are aging nice!
Crockett & Jones for Ralph Lauren Cordovan (Marlow, Darlton, Gifford, Garran, Lindrick, McCallum, Rhett) - Page 517
Not sure if the pair you quoted are made up differently, but a GMTO just recently got approved to push forward for a pair in brown shell. I imagine getting 12 more together wouldn't be too difficult
yes, I was curious because I have seen that in different shapes and sizes on my shells, but usually after the color starts to fade a bit. I think it is just from the underlying color and not due to any mistreatment. I've found no way to get rid of it and just consider it part of the developing patina. I did try though the first time I saw it. I tried Saphir cordovan cream and Renovatour and it didn't make the slightest difference. I think it's just normal for shell.
I think you're right. Shell fades from lighter to darker or vice versa. See these captoes esp. my left one. You can see a dividing line/murkiness between darker and lighter. Eventually, it will all turn one color. Apologies for non C&J content.