Looks really smooth indeed!
Reading the write-up on the Classic And Sportscar website, where it's also offered for sale, it seems to be a really professional job, as BB says.
Initially I thought the high level brake light looked like and after-thought, but after thinking about it some more, I think the high-level brake light is a good use of the left over space resulting from using a flat MGB GT rear screen in the curvy Jaguar roofline. It would have looked better, I think, to have a curved rear screen too, but I guess there could be more than a few reasons why they went for a flat rear screen in such a big job. But everyone's a critic, as they say and I'm sure that team knows just a bit more about car engineering than I do (I felt chuffed to bits after changing my X300's rear exhaust silancers without breaking things
Damn fine piece of work, really. Would have been a nice model option for Jaguar to have offered back in the day, alongside the estate Eventer and the regular XJS