In the cupboard this circular part is wet after a night in the van and a rainy night. Van was well ventilated and there was a very small about of condensation on the kitchen window, hardly noticeable. Does any know what this is . The rest of the cupboard is dry
The picture shows the access cover to the waste water tank beneath the sink.
If you have a leaking window seal and faulty window drain there will probably be water on top of the tank and running down this access cover. Search for "window leaks" for days of reading. If the window isn't leaking there could be a leak from the tank or associated pipework.
My money would be the window.
We have only had our Cali for 8 or so weeks and highlighted this problem under warranty- it transpires there are slit drains in the guide grooves for the sliding windows. Check that these are not blocked before going down the route of replacing window seals. Hope this helps