HI, P.,
You may not believe what I am going to ask...do you use fabric softener? If so, try not using it and see if anything changes. That is what happened to us. Our daughter never had any accidents in bed, but then she started having them every single night and the only thing different was that I had used a liquid fabric softener on the sheets. (And, because she was wetting them everynight, I washed them everynight and used more fabric softener!) Once I stopped the fabric softener, she stopped wetting the bed at night.
I probably wouldn't have caught the connection right away, but my daughter has a sensitivity to Blue#1 and from having read about that I had recalled something about fabric softener/bed wetting. Fabric softener is apparently one of the most toxic substances you can bring into the house. Her reaction could have been caused by Blue#1 being in the softener, but I could not confirm if that was in the softener as the company won't release ingredients without a doctor's note. Anyhow, what I read online showed a connection in some cases between bedwetting and fabric softener. Good luck!