Ok I thought I wasn't clear. I just confused myself reading my own post!
What I mean is, when the wheel is unplugged, or I'm using the keyboard, the highlighted selection stays where it is. If I have my wheel plugged in, it's like I have my foot on the accelerator, when I clearly haven't. If I don't calibrate the wheel, then there's no problem. If I do, then this problem occurs. There MUST be a way to switch this "feature" off surely?