Just did a quick test downstairs with it and a poor .965 EP ( was supposed to be looking at the leak in the car radiator !! ). Looks more than suitable and is almost exactly f6 (360mm). Also just happens to fit into a Xerox waste toner bottle plastic tube ( black and rigid ) which also just happens to be the right length and found a screw thread focusser that just fits the tube via a plastic coupling. Not bad for a hasty 5 mins work.
But the radiator is still leaking, split header tank dammit !

There goes my slush fund for the time being...