It doesnt look good with your cancellation history, but there is another avenue.
Ask Motability for advice, tell them the problems you are having and ask if they can get some aids fitted to your car. They can fit a strap to the bootlid that makes closing easier, and sure a carpenter could make a box that would raise the bootfloor level with the boot opening.
Better advice from other members on the aids for getting in and out of the car could also help you.