if the barrel is stuffed you simply fit a new barrel which will then be built to match the key you have

a simply job and no, the wheel won't need to come off, just the cowling for the column

if the sterring lock is buggered then it's normally the barrel that hasn't turned back to it's "key removed" position, so that would point to more barrel related issues

not sure why though, it nrmally only happens if they are worn