Also many are so tight that it needs a LGV to keep more left than right on the approach to turn without mounting any part of it
Very true. But, just to confuse the issue a bit more, some roundabouts you approach more to the right than left to avoid the left kerb on the way into the roundabout. And this, dear listener, is why good instruction is vital to make sure you know the difference!
Good luck all,
Pete 