I don't have a multimeter but I have ordered one, should come in a few days. In the mean time I did hook up the battery to a battery maintainer and let that charge overnight and now when I get in the car the screen on the dash comes on but not the large screen in the center, it says to book it in for a service and is showing charging complete at 0 miles. When I try to plug the charger in it wont accept it, the only way I can get it in is by holding the release down in the boot while pushing the charger in and when it does click and lock in the light next to the port is red instead of green, it does eventually switch to green but does seem to charge the car at all. And I can't see how the car would have discharged all that energy over just a few days, it was fully charge and had 160 miles on it, so think it may just be the dash showing wrong. I have booked a service but that's not gonna be until 20th of July.