This year I changed it up a little bit, treating it much more like the Primula Auricula. It is in a very gritty compost and I keep it pretty much out of the rain only watering when I think it is running dry. I do however keep it in a more shady position compared to the Auriculas. I did fear for it for a long time, it lost almost all the original leaves (you can see one of them on the photo, all brown and yellow). However it is steadily growing a new flush of leaves.
One thing that bothers me a bit is that the leaves seem to be smaller and less elongated than the original leaves. Primulaworld.com has some good photo's of Primula Melanantha in situ and you can see the leaves are supposed to be much bigger and much longer. Going strictly on colour I think my Primula could probably do with a little bit more sunlight and I might even give it a very light feed. Lets see if I can get it to survive for a little bit longer.