Sorry guys I guess I've not been too clear. nobody was banging out a cv joint. The splines through the hub, where the 37mm nut is removed from, were freed by banging the end of the shaft inwards towards the diff.
Nothing has been removed from the diff, the shaft is removed by unbolting it from the drive flange which remains in the diff. so no oil lost.
All wheel nuts were tight.
Smaky: in an earlier post you said that if the CV joint was left to knock it would result in damage to the diff thats what started me worrying about taking a hammer to the end of the drive shaft, Am I being paranoid.