I can't add much to the good advice from Slunnie and discowhite and others. But don't even think about 4.7:1 rover R&P. With rover R&P 4.11:1 is the way to go.

I have 4.11;1 diffs in my disco and the speedo reads fast with 33"'s.

If you take it easy with 35"'s you should be reasonably happy with 4.11:1 R&P, rovertracks axles and cv's and your choice of lockers.

If you want to wheel it hard with 35"'s, then you should think seriously about fitting macnamara hypoid diffs and 33 spline axles and longfield cv's.

I would even recommend that you go this way in any case since you haven't committed any $$ to other drivetrain stuff yet - many people start spending on lockers etc, then can't justify scrapping what they have already bought and then have to compromise/suffer forever. You would have a better choice of gearing for 35"'s (probably 4.3:1), the best air lockers going, and the strongest R&P, axles and cv's that you can get into rover axle housings.

The next step up is to fit patrol/landcruiser axle assemblies - this involves more work but with your lift, the increased wheel track will be an advantage.