Thank you
ta-ta and
lucy92. I used the saddle soap per your suggestion
The shoe shops had nothing btw. I think they would prefere if we just bought new stuff
I used the saddle soap last night (and had a sensory trip down memory lane... I washed and scubbed my mothers saddles when I was a child

). I am very happy with the result. I could have scrubbed harder and gotten more off, but I am lazy and the original treatment of the leather conceals the color transfer quite well.
I did read somewhere that saddle soap should not be used on handbags. Something about the PH being too high for delicate leathers. I reasoned that my handbag is not a Chanel "baby-butt" soft leather and delicate bag, but quite sturdy. Also, the bottle said "ALL LEATHERS"

My bag kind of smelled like "new saddle" too
The back (that was stained) now matches the front of the bag (unless you study it closely

). I will try to add the shine back to it after the leather dries completely. Right now it is a bit matte where I cleaned it.