Andy murray

Hello fellow jaggers, I absolutely love my xf 250 3.0 d 2009 but I’ve had a problem that has now got a lot worse, when reverse is selected on the auto box it stalls, sometimes it will idle backwards but any touch of the accelerator it just cuts out. It’s totally fine in any of the forward gears, does anyone have any ideas please, p.s I’ve cleaned the throttle body and it’s still doing it many thanks in advance Andy