Removal of a battery is the simplest thing in the world you'd think - not on a French car. I watched a YouTube video and I thought - that's it! I found a plastic tab you should press to release the bottom of the battery from the tray but it's still stuck. You need to remove the thing to the left of the battery - whatever it is and I can't find the release button. In the photo it's the thing with the yellow arrow. It should be pulled sraight up but something is holding it back. What is it?