Nope, the stripper arm mounts into 3 screw holes in the base assembly (15) on the diagram, so it's fixed in relation to the base. From page one:
On the 28ST the self-tailing arm (2) is fixed in one position.
Ensure correct positioning of the self-tailing arm, before marking the bolt holes."
There's a very, very faint diagram on page 2 (I have to tilt my screen to be able to see it) that shows their suggestion of the arm positions, but what I don't know is if that's because that is where the grinder would typically be in relation to the winch, or whether that's the position to allow the sheet to tail into the cockpit, loading on the winch etc. If the latter, then fair enough, if the former, well, I mostly sail alone so I'd want then more orientated to the stern where I am