@Debra481 “So far I have had 2 bookings and they were both under the impression that the price was for the whole apartment including both rooms.”
When guests are searching, they will be perusing and inquiring about many listings at once. Therefore it’s easy to get details confused. I see you have two separate listings for each room, which is a good way to approach what you’re doing, but you have pictures of both rooms in the one listing, and make references to different rooms as well. I believe this is adding to the confusion.
You should make each listing only about that one particular room, and only mention the existence of an additional room, “which will be empty and inaccessible during your stay.” You need to be able to lock the room that isn’t to be accessed by the guest.
Have a look at my profile and compare my two listings as I do the same thing you’re doing, but you’ll see what I mean about making them very distinct from each other in the descriptions and photos, etc.
If you want people to be able to book the entire space with both en-suites available to them, then create a third listing as such.