You need to push the fuse box on the right over towards the wing - as the battery tray sits under it - those 2 connectors you took bolts out of on the right. Also unclip the loom out of the clip at the bottom on the right hand side of the tray. Once you've done that you just pull it up
I think it was the loom clip that got me then, was yanking at the case a bit but didnt wanna go too hard incase i snapped something, so much effort just to remove the battery case
The attached may help Also remember to unclip the battery drain pipe from underneath, to allow it to be pulled out with the tray - speaking from experience