First point is chassis production VIN number.
You have your heritage certificate?
Oddly, JCNA (Jaguar Club of North America) has a guy...president of the national for a while...who laughs....he has scrapped quite a few, way beyond any hope of salvage, so badly rusted or bent...and save the plates off the scuttle/wing.....and sees cars listed on the Jag Database with the numbers from cars he has personally scrapped and saved the plates from.
Interesting dilemma should he decide to claim ownership with titles and VIN plates in hand...showing those aren't right....or even just the title.
So, what's your VIN?