Thanks Alan and everyone.
PDFSAM loads and works fine on my Vector 5.9 system. It splits and merges pdf files and probably a lot more.
For the heck of it, I just split a 3 page pdf I was working on today into 3 separate pages with pdfsam split and then added a new page 2 and using pdfsam's merge, merged them all into one 4 page document. No doubt I will discover it does more after a bit of use. Its pretty intuitive when it comes to splitting and merging. I know I will use it a lot.
Perhaps I won't need pdftk or cpdf after all.