Well what you really need are lights that are designed and made to minimize the light that reflects off of the water droplets.
Some of the E-code H4 headlamps are very good at this.
You may actually have some better access to Cibies than we do in the States. That's going to be one of your better, some one would say best, choice for current production lamps.
Not cheap, and will work best with power coming straight from the alternator using relays.
Pair the lamps with a
good set of H4 bulbs. If you see a bulb with +50, it will provide more light output with some loss in lifespan.
Of the LED headlights, the only ones that seem to be good and truly meet either US or UN headlight standards are JW Speaker and the ones made by Trucklite (including Peterson). They will cost more than the Cibies, but shouldn't be as hungry for power. None of the stuff I've read about them specifically focused on performance in fog and rain. A good place to search (or join and ask) is Candlepower forum.
Here's a couple of threads to get you started.
Headlight decision - Cibie or LED?
LED Headlight Question(s)
Fog lamps mostly help as markers (so others can see you) and very short range illumination so you can folow the edge of a road - slowly.
