Just can't seem to find clearance on the left rear side to remove the battery cover and then the battery. Do I have to loosen the rear body plastic or is there a trick that I do not know about ? Tried tilting forward and there still is a problem.

 

I removed and replaced mine a couple of months ago without any problems, but now I can't remember what I did that seemed to do the trick. Have you tried lifting it up out of the tray at the left end (as you're facing it sitting next to the rear wheel) first, and sliding it out that way? Or perhaps tilting it away from you and sliding it out towards you? Sorry, my quad's not here so that I can go and have a look.

 

I just pulled my battery today to store it in a warm climate.
I had to tilt the battery as far as it would toward me before the ground cable reached its limit, then give the cover a healthy pull. It did catch a little, but it came off. I remember this summer I pulled it off the same way. It was easier to install them remove.