The Jag isn't a bad car and it looks a lot nicer than the 5 series of similar vintage. I really enjoyed mine. I just hit an Uber with it and needed shot of it
I think I only paid £30k brand new for my XF black 2.2, so 15k for one of this vintage (the facelift ones are big improvement) seems high.
There won't be a learning curve, you are being careful but overly cautious. It is a luxo barg, quick in a straight line, too big to do too many twisties in, and basically designed to be boring.
I don't drive like a nutter, and tend to drive quite carefully, avoided couple of crashes as ive seen issues up ahead etc. Saying that I'll as much as I would like say try a Yaris GS I would probably break it