Hi Darren, the parts and manuals section has two illustrated parts lists for Greenfield Evolution 13-32s, one with a traditional Greenfield solid axle, and one with a differential bolted to the side of the final drive sprocket. The bolts go all the way through, and apparently hold the the opposite side-plate on as well as holding the sprocket on - the sprocket is the other side plate. It appears that you service the diff by removing the bolts, and probably one of the side plates unless you need to remove both.
There are two common ways for diffs to be designed: as a bevel gear diff, or as a spur gear diff. Modern cars (those made since about 1940) invariably have bevel gear diffs in my experience. However the Greenfield diff is obviously a spur gear type - it could not be so flat if it were a bevel gear type. The side plate, opposite to the sprocket, seems in the illustration to be much thicker than the sprocket. This suggests that it holds the axles for the planetary spur gears. If so, it would make sense to remove the sprocket first, leaving the side plate in position, and take a look inside. The long axle shaft (the one on the sprocket side) will come off with the sprocket, and you will probably be able to push the short shaft out through the housing if you want to. I'd try that first, and only separate the side plate from the housing if that turns out to be necessary for some reason.
