Yeah I tried that but it doesn't seem to work if the object is being driven by another object's rotation. If I set limits and move the object without using the set driven key then the limits do work, but then i'd need to keyframe everything manually, its ok now though as I think i've located a plugin which does what i'm looking for. Thanks
Incidentally, i'm still pretty newish to the whole forum idea, how do you guys get the little images next to your name on your posts? (I hope i'm not going to kick myself for the answer to this...)