I had remarkable success with products from LEATHER WORLD TECHNOLOGIES. (leatherworldtechnologies.com) I purchased two products for the upgrading of a leather armchair. The chair had cracks and discoloration on the leather. I sent them a small piece of the leather to match and received back a perfect match dye. I used their leather filler on the cracks and then the dye. The chair finished like new.
The leather filler was $15.95 for a jar 11/2inch high and about two inches round I did one arm and still have most left and the dye was 24.95 for about 8 oz.
They sell dyes for many cars, but I would suggest you send a sample color and its Jaguar ID.
Please note I did not repair a jaguar seat and pass this info on FYI