I memeory servs me corectly a 200 TDI defende still used 48mm bushes in the radius arms, which was the same as RRC axle up to 1985 (when they went EFI). Later RRC/disco and 300TDI defenders axles used a wider bush 52mm in the radius arm, so by rights if you used a later spec axle you would need the radius arms changed as well. Having said that in theory you could fit wider bushes in a narrower arm, but it's not an ideal solution.