It appears my mate has the same sine vice. He was happy to dismantle it. Two allen bolts hold the fixed jaw in place and this has a shallow key running across the width of the jaw. The main vice plate is held down by 4 pairs of allen bolts and when these are undone and removed the vice plate can be lifted off the upper moving section of the sine assembly. The vice assembly is located by a wide machined key running the full length of the vice. Slides in nicely without any play.
So the answer to my question is yes it can be dismantled and easily put together, the two keys should ensure accurate registration of the main body and the fixed jaw.
Colin