Just for info in case anyone else has the same problem.
Called out JLR Assist and they say one of the struts is and has a bulge in it.
They need replacing.....
Thanks for your help all :t ...
Hi Guys -My D5 has yet another gremlin where by when I press any of the auto buttons or key fob to close the tailgate, it get to within 12" of closing and then opens up again?