I'm now even more confused! Looking on a popular auction site there are plenty of r380 boxes but some say they will only fit discovery models! Is this just the bell housing differs and that I can reuse from mine or is there something mechanical that differs?

I have a 2004 110 and am pretty sure I need either a replaceme gearbox or at very least a strip down and rebuild. My question is looking on the internet I cannot determine what code box I wi need? Any help would be greatly appreciated .