At the end of a BH weekend, it’s kind of comforting to see that the MN arsehole quota is being maintained at optimal levels!
OP -you are probably asleep now, so this advice is for tomorrow. If you have to leave for work in the morning, pop a note through the door. Don’t go into huge detail, just along the lines of “there has been an issue with my pet in your property, please knock/call me asap so that I can explain and rectify”. If you don’t have to go to work, I’d be keeping an eye out for when they arrive and then go straight round there - a face-to-face conversation is best.
Dont worry about HUGE expense. I can’t imagine an expensive rug would be left in there while builders are working. You aren’t going to have to replace the whole floor, maybe just 3 or 4 floorboards.
As an aside, I’m kind of laughing at the “cat will find something to drink” comments. All loos here have the seat down and there are no dripping taps.
It’s definitely worth looking at trying to secure your garden re the cat. Have a look at this website. Yes, it CAN be expensive. But if you or DP is handy re diy then you can save a bit by installing yourself. I can’t access photos now, as they’re on my old pc system, but I had this on my old home around 13 years ago. Would definitely recommend, they figure out a solution for pretty much any configuration. I’m very lucky in that my cat truly is a garden cat. He has zero interest in popping over fences etc.
As for those who laughed/questioned re crab sticks. I’ve had my boy over 13 years now - I’d have to google this too, I have no idea if he’d like them!
And I would probably, at some point, have considered ham. Maybe not through the vents, but definitely through the slightly open window. Only reason is that lots of crap ham has a “high” water content, so there could be a chance of food and water content at the same time. Obviously a short-term solution, but trying to make the best of a crap situation.