Defender 90 2010 Puma XS Diff seal leak

Noticed a few drops of oil on the drive recently and traced it to the rear diff seal. Looking at the diagrams online a large bolt holds the splined flange onto diff. Any dangers with this job that anyone has encountered such as preloads or clearances with pinion to crown wheel? What are the torques settings when for the bolt during reassembly. Thanks

Pinion bolt 129Nm, took me half hour last time i did one.