Well the 2 batches of mead (one with Orange Blossom honey, the other with Spanish Lavender honey) have been on the go since the 5th, so that'd be about 13 days. I haven't checked how they're getting on gravity wise, but about 4 or 5 days ago, I topped them up.
Now that in itself shouldn't have needed much thinking about, but I don't recall adding any tannin (I'd have to look back to the recipe........) so I decided to top them up with grape concentrate and RO (reverse osmosis) water. I took a 900g tin of "Youngs" white grape concentrate and split it equally between the two DJ's and then topped them both up to just below the neck with RO water.
The bubbled a bit more too start with, so now I'm planning on just leaving them to finish. Then I can have a taste and decide on what's to be done from there. They're still bubbling at a rate of about 1 bubble ever 2 or 3 seconds, and while airlock activity isn't an accurate way of checking fermentation progress, it's fine for me, for the moment. Once they've slowed even more I'll check the gravity, just to make sure that they're still Ok.