In any engine swap these days first thing you have to think about before the nuts and bolts is the engine management system. The "new" engine will bring with it its own computer and wiring harness, and you or someone has to know how to program all that to work, and wire it up to work. This is a more formidable obstacle than just fitting in the engine physically if you know what I mean.
Generally the people who do these swaps have the benefit of many pioneers who have worked it all out and posted the info on the internet---like people doing Honda engine swaps. But in your case, I'm not sure many, if any people have done this, so YOU become the pioneer, which is not so much fun.
I'd say your best bet is to search out and participate in Rover forums and ask around if anyone's successfully done this and how they did it.
I sure wouldn't go in half-baked and unprepared to deal with the computer stuff.