Hi Owen and Susan, Hi Naz,
May I wish you all my usual warm welcome to the CameraLabs forums.
Naz, I have a feeling that you are talking about Flash Exposure Compensation (page 101 of the manual) as Exposure Compensation is not available in M or Basic Zone modes (manual, page 173). On your second question if, for example, you are in Av mode then you can't directly change the shutter speed as the wheel behind the shutter button changes the f-number. If the auto-exposure calculates a slower shutter speed than you want then either shoot in another mode, Tv rather than Av for instance, or increase the ISO and/or decrease the f-number.
Owen and Susan, This is trickier.
I assume you are setting Exposure Compensation using the procedure on page 93 of the manual. Don't get this procedure and Flash Exposure Compensation (page 101 of the manual) confused as they both use the same portion of the viewfinder and/or status displays. The only visual clue you are setting something different is the presence or absence of that little lightning bolt! That said, I don't know why the setting isn't being memorised during power off. I've had a quick look through the manual and I can't find anything to explain this. I'll have a little rootle on the Net and if I come up with anything I'll get back to you.