Needed to remove front half shaft, got it off OK, workshop manual says to replace in reverse order, to get off I used a slide hammer. At the diff end of the shaft there is a short length of spline, then as the manual calls it a circlip, its a split ring that needs to compress, then there's the longer length of spline. I am happy I have end section to slide onto the spline OK as when I turn it I can hear the gears turning, the question is how to I get it to compress the ring and then slide in the full length. If I follow the manuals do it in reverse I wallop it with a hammer, but, I don't want to damage the diff, any suggestions? 

Usually when you remove the circlip (work it off by using a small flat blade screwdriver) and usually the shaft will come off with a soft faced hammer (copperhide or plastic)