I replaced the rear backing plates on my fn2. It was a bit of a faff, wheels off, calipers off, discs off then undo castle nut and pull wheel bearing from hub. Ended up shearing two bolts one side and three the other. Had to drill them out and re-tap the hole with m6 tap. I believe the ep3 is the same, easy enough to do just take your time use penetrating oil on the bolts and have replacement bolts ready as they will likely snap. I believe they were 25mm m6 that hold the backing plate, three each side with washers.