I have these items available. I bought them for my 1987 XJ6 in the late 90s, and they’ve been in my garage since I sold the car in 2008.
Both items are authentic, and were available as add-on options through Jaguar parts. As I remember, the tool kit had been standard in earlier years of the XJ, but was made an option in the III series.
Okay, these are either priceless, or no one cares, right? 
tommykat1,
Well, I’d say that it’s a little of both. 
I like the OEM mud flaps and have had them on my two Series III XJ6s and XJ12. Some people like the mud flaps and others don’t. I like them particularly for the protection that they provide to the painted areas behind the wheels from rock damage. I also have three sets of the optional tool kits although I never use those tools.
They all have value and sell regularly on eBay. You can get a rough idea of going prices by keeping an eye on eBay. You can probably sell them on eBay or by listing them in the Jag-Lovers Classifieds.
Paul
In my back ground, mud flaps had a bad rep!! Biased, yup…
Tool kit, great… Not much in my “original”. Jack and handle!!! Both and the roll, pristine. No use. except by me, the jack in a non car use…
Carl
The mud flaps look GREAT on the car, IMHO, but I understand the bad rap, which, ironically, is why I bought this second set, never used.
My wife used to aggressively back up the car, and on more than one occasion a flap would get sucked under a rear tire and pull off. This was salvageable, as it could be attached back in place–if you found it, of course–but the design was obviously not well thought out. (It’s British, after all!) So I bought a second set in case I lost one.
Thanks for this, Paul! I’m new here and didn’t think to check for a classifieds section.