Well I had another go.
Pulled the nut off and added new Loctite then re-installed the nut.
Torqued it up to 100 ft/lbs using the new thin walled socket. Then went to 125 and finally 150 ft/lbs. That took some doing (been a while since I did weights like that in the gym. My wife keeps reminding me I'm almost a pensioner).
Used a set of luggage scales to check the rotation torque and it's in the ball park. Took it for a run & all's quiet
The front diff looks a little damp around the seal . . .