Free Wheeling...........

Would i be able to jack my series 2 up onto 4 axle stands in order to test the 4wd system and see it working as well as have a good look and play underneath?
Thanks

Better just to jack up (and safely support) two wheels, front & back on the same side.

steel wheels? or tyres? So how would you allow all the wheels to spin freely if they had to rest on tyres?

Two wheels on the same side in the air.
MAKE SURE THE VEHICLE IS SECURE, AND WHEELS ON THE GROUND CHOCKED.

High Range
Engage a gear and apply the hand brake. If Free wheel hubs are fitted make sure they are both locked.
Try and turn the back wheel. That should be locked (it may rock back and forwards through ten degrees or so, that is play in the diff and usual, but you should not be able to turn it)
Try and turn the fronmt wheel, that should turn.

Select 4WD (push yellow knob down)
Try to turn wheels again, neither should turn.

Reselect 2WD (pull red leaver back, yellow knob should jump up, push red lever forward again)
repeat tests to check it has returned to 2WD

Select Low Range (pull red leaver back)
Repeat test, should be in 4WD

If the transfer lever hasn't been used for some time, you may have to move the lever, turn a wheel, then push the lever again to make it engage properly

So the 2 front wheels or 2 rear wheels do not have to turn together?

No, like all cars you have a differential, otherwise you would not be able to go round corners.