Well found out that it is easy to change and as I was told to purchsa the full unit at a large cost I'm glad I didn't
All I did was go to the reckers and get a decent tensioner and unbolt the tensioner (that was the hard part as it fell into two bits) and bolt in the other. Now there is one thing you have to remove #2 as you can't get to the bottom bolt on the tensioner. By the way thanks fro the drawing it helped heeeeeeps.