ha ha, found it. Here's a copy of a post by a bloke called flyod on the Patrick Eggle forum (can't link to it as you need to sign in). I can no credit for it.
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This may be of help or interest to those people that didn’t know that you could change a left handed Sperzel to a right handed or vice-versa. You would therefore be able to change a set of six in line to a set of three a side or vice-versa if needed, or to change the hand of an individual spare to replace a broken one. It is very easy, all you have to do is: - remove the screw located at the end of the tuning key, pull the key off, followed by the small black washer, and then the bell shaped sleeve. Push the centre spindle out, making sure that the locking wheel is loosened so that the gears can move easily inside the main body, a little wiggling and turning may be required to release the spindle. Insert the spindle into the opposite side of the main body, (again you may need to wiggle it about a bit to get it seated hard up against the main body), and assemble the other parts on to the spindle, all that’s left is to adjust the tension of the screw to adjust the tension of the tuning key, job done.
floyd