Fired up the Feuerhand lantern this evening - I'm using citronella lamp oil, which is good for outdoors (but not recommended for indoor use).
It's a really lovely bit of kit - suprisingly light-weight, but it's well made and feels very robust. Depending on the height of the flame it's rated for approx. 20hrs constant light, which should see me through a couple of nights at a Meet.
The light is as Mike described - it'll never light up a whole room enough to perform microsurgery, but it throws out a decent amount of light, and as a camp lantern it will be just what I was after.
Not the best pic I'm afraid - hurried before the rain came back! - but I'd recommend both the product and the seller.
My thanks to Graham for the recommendation.