If I'm looking at the inside surface of ex-box face on, do I turn the ex-box nut clockwise or anti-clockwise for gear 14?

I can't remember, but there's no need to.  You can change gear with an 8mm spanner while the wheel is in the dropout,  turn it to one end, turn the pedals, turn it to the other and you'll know.  I frequently forget to change gear before disconnecting and do the above, it takes a couple of seconds. 

From memory, use a spanner to turn the gears to one of the limits, turn the shifter to the corresponding limit and then fit the ex-box. Finally check if you have the full range of gears.

I've had the leakage problem in the past. You may want to draw off a little oil from the hub. As already noted, there doesn't have to be a lot of oil in the hub to be able to keep everything lubricated. There's the risk that when doing a flush and refill of ending up with more oil in the hub than at the start unless you've been patient in trying to extract every drop.

When my hub was new, I had a frightful moment when there was what appeared to be a pool of oil underneath it. If I'd been living near the supplier or the manufacturer of the bike, I would have delivered it back to them that day with a rocket and a demand they fix it at their own expense. Fortunately for my dignity, I live in Ireland and there was no instant means available to return the bike to Germany.

On investigation over several occurrences of the disturbing event, I noticed a preponderance of water and very little oil in the small pool. Since the hub had not been submerged, I started wondering about environmental factors. The bike was standing in a passageway in my town house, near an outside door of wood but a large half-circle of glass over the door, causing the bike to be alternatively in sunlight -- it was a pretty hot summer shading into a muggy autumn -- and colder shadow. Cycles of heat and cold could account for a small pool of water on the stone floor. We also saw it in the winter, when the heating goes off at night.

In those days I filled with the recommended 25ml of Rohloff's own All Seasons Oil.

Someone on the forum mentioned to someone else in another matter that the Rohloff vent is through the axle.

So here I then had two facts which together would account for a pool of water with a little oil in it.

Over time, as I understood more and more about Herr Rohloff's extreme devotion to the Engineer's Religion, also called Cover Your Ass, which in this case was practically expressed as, "12ml in the hub is enough for me, but thee are required to put in 25ml."

I filled with less and less oil and eventually the problem disappeared when I got down to filling with 16ml of oil. It's years since I last saw evidence of the "leak". These days I fill with 14ml to allow for spillage because measuring and inserting the permitted 12ml isn't a certain procedure in domestic conditions when you don't have the hub on a bench before you.

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It is a well known fact that once the gears inside a Rohloff box are coated with the correct oil, it's good to go until the next service interval at 5000km/3000m or one year, whichever comes first. Extra oil swishing around is superfluous.

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My advice is therefore not to panic, to perform a full service with 14ml of Four Seasons Oil, ending with fitting a new stud in the Rohloff oil port, and to watch whether anything comes back out in the next few days.

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You must take your own counsel with an expensive hub, but I would not hesitate so soon after putting fresh oil in the hub, if waiting for a service kit or stud to arrive, to ride the bike as long as the piece of tape PH advises is across the port (more to keep dust out and stop oil getting on the braking band of the rim, than to protect the gears against running dry). The logic here is that even the Cleaning Oil is actually also a running oil, specifically for very cold ambient conditions, and some of that, plus some of the All Seasons Oil that you put in, will be sticking to the gears.

Good luck.

I do not understand your post, did you ride your bike and park it at work without the small screw?  If so, a puddle does not surprise me.

No the screw was in (the old screw, with less sealent on it), and fairly tight. I tightened it a bit more (but am aware overtightening is bad)

As I said, the small black pool on the floor beneath the hub seemed more watery than oily, which puzzled me a little...

My hub has always had a bad leak.  I have a side stand for my bike, the bike leans slightly to the left when not in use.  And the leakage appears to come out of the EX box.  I am pretty sure that I have a bad internal seal on my Rohloff.  The exploded diagram shows a seal that keeps oil from leaking into the hollow axle for the quick release skewer.  And my skewer is always covered with oil, thus I suspect that seal is what leaks on mine.

I do not understand your post, did you ride your bike and park it at work without the small screw?  If so, a puddle does not surprise me.

I use blue (removable) threadlocker on my Rohloff oil screws.  On this forum, Dave W. (former employee of SJS) commented that what I was using was oil soluble threadlocker and that I should use something else, but I keep using it anyway.  I often put a piece of black electrical tape over the screw after I change the oil, mainly to keep the screw clean so I do not have grit inside where the Allen key goes.