Harrison M300 lathe help needed

We've recently acquired for our small workshop, a used M300 which had a problem with the screwcutting gearbox. It would only feed on certain ranges/knob position combinations. We got the lower gearbox off ok, but we made a very, very stupid mistake; We didn't take any photos or make a drawing of the orientation of the change drum sections and gear positions before stripping it. A foolish thing indeed as it turns out. Does anyone have a photo or drawing of the arrangement of the gears etc correctly assembled? The manual we've got only shows an exploded view. Any help at all would be greatly appreciated. thanks, JB