Whilst posting random fings on this forum, I've been doing my second oil change. Here's some observations.
Only got about 20ml of fluid out, despite putting 20ml of cleaning oil in, but it's been over a year and probably well over 5000km since the last change and I had a couple of leaks when the bike was on its side.
(Actually, now I come to think about it, I did a mini-tour a few months back that involved a bit of wild camping. I left my bike on its side overnight in the woods to make my little camp less visible to gamekeepers, landowners and other folk who'll be sorry when Scotland's enlightned laws make it down here. Anyway, probably didn't help the leakage.)
Reused drain screw, with a dab of Loctite 243.
Don't get the oil on your carpet, it's very black. This seems like a good place to plug my favourite EVER cleaning tip learned through many years of inappropriately maintaining my bike inside various student/rented flats/houses:
Got some mucky black stuff on the carpet? No probs, just spray it with GT85 and rub with a clean rag. Stain's gone! (Yeah, yeah, test on an inconspicuous bit of carpet first, etc.)
Right, now to fit a new BB and chainset and reverse the Rohloff sprocket. Am I pushing my luck for today...?