Ohhhh, you poor thing - I can feel your kind of fear and embarrassment from over here...and wondering how you can solve it all....
Have you been to that particular place before - or is it new to you all?
A couple of years ago, we took Harry to a 'self-catering holiday home' over here, on our Norfolk Broads - it was a fabulous, hundreds-of-years-old converted windmill - obviously on the water.
We had to go and do some groceries shopping, so Andy and I hopped on our boat and left Harry 'in charge' of the windmill. As we sailed away, I could hear what sounded like a banshee x flock of geese x cat-being-murdered
Obviously sound really carries on the water....
People were actually circling and staring, trying to find the source of this rare breed....
I must admit, it did take him a couple of days to get used to being left (and I'm only talking an hour or so - whereas at home he's fine, as little Barney is). Really, all you can do is do what you're doing....but I truly know how you feel, and hope it sorts itself out soon...good luck, and hope you manage to be able to leave him with a peaceful mind soon
xx