Welcome to the Club, Edmund.
 
	First, let me say that you have a very nice car  ---  nice colour too.
 
	At a guess, I think the issue could well be a fuel one.  I have not driven a manual Jaguar for over 3 years, currently having a 2.7 Diesel S type - but as you car picks up better at a slower speed and is OK  when it gets going I would suggest a fuel system cleaning additive  ---  under a tenner  --  Diesel Magic, or Wynn's ---  that will probably assist.
 
	Regards,
 
	Peter.