Update. managed to get slide joint apart again cleaned it all up. and as for markings all i could see was a small lug on one part of the union. Went back under disco couldn't see anything that could possibly be an alignment mark. However I decided to take a look in the prop-shaft to see if there was an obstruction. Only to find what looked like one of the splines missing. Upon closer inspection that was how it was made. THOUGHT!!!. Line the lug with the missing spline and what you know all went together very easy. No hitting or banging. All done now. Works beautifully Thanks Guys and Thanks Buster for the pics and tips on how to do stuff. Happy chappy again now. Now time to replace lift pump. But that will wait till during the week. Cheers again all