I think the composting loo needs to be at 14 degrees or more to start working. In spite of a warmish bathroom, it is still sitting on a very cold floor. The Polycore is very good and the rest of the walls in the van are comfortable. But I think the floor under the compost container is very cold.
These loos take a while to compost toilet paper. So, as a big toilet paper user, I put in 500 compost worms two days before we left home, without realising that these worms pee 60% of their body weight every single day. It went great for a few days and the compost level dropped by a good two inches with no loo paper in sight. Then it all turned into a watery mush which had to be carried down and emptied at the dump point. But the fan kept the smell out of the van.
So we started again with fresh peat just before our heater failed and a similar thing happened because the loo was extremely cold. So we emptied it again and did a really deep clean.
A new peat brick plus two 150 watt work lights in the bathroom with the aircon running 24-7 seems to be helping. We are keeping the flap open because water was condensing inside the compost container, agitating more regularly and adding more dry peat if the bed looks a bit too damp. We are also using the amenities block a bit more often.
When we get home I plan to rig up a little 12 volt heating pad under the compost container to keep the lower surface at about 50 degrees. They are cheap and draw only a couple of amps or so, to be used only in cold weather.
Keith