Evening , I have been search the treads but not found an answer to my question yet , my disco rear diff (3bolt flange) is toast and I have been given a 4 bolt flange diff and rear prop. Can you just bolt these up and all will be well ? Thanks in advance

From Ashcrofts site: The rover type diff comes in 10 or 24 spline, 3 or 4 bolt drive flange, the 3 bolt flange model was used on the later RRC and D1 rear and all D2 rears, 3.54 ratio and imperial or metric

So as long as the ratio is the same (3.54) then it should just fit ...