The door could probably be opened with a Slim-Jim but that leads into the question of closing it again…
If the outer handle and inner cable broke that often points to a latch mechanism seizing up or getting gummed up.
I can’t speak for the difficulty of the job as I have very little experience with Jaguars but the price of parts and possible aggravation due to access of the latch leads me to agree with texases about finding another door possibly being the best option.