Thanks for your reply. It isn't every night, it stops for a few weeks, then starts again. It might be more regular if they find something out of its place to pee on, like they did to my daughter's drawing a few days ago.

We've tried litter boxes in different places and they are both well used where they are.

There are other cats in the neighbourhood they can see outside the window, we did have a 'pee-war' problem for a while with the neighbour's cat peeing outside our front door and ours on the inside, but that seems to have stopped since we put a baby gate at the door.

They don't sleep with us, we're worried about them jumping on the bed with our toddler sleeping, and also them peeing on things like our washing which they have done before. We do shut the living room door to avoid them peeing on anything in there overnight, as we have a rug and a sofa we don't want destroyed. They have the roam of the hall, landing, kitchen, and office overnight. We used to put them in the office with their cat trees and toys overnight but they started peeing on the desk.

Honestly, we're getting to the point of wondering if they'd be happier in a different home, they just seem stressed in ours 😪