Hi
So I have finally found out that you can in fact do this. But it's a little long winded. I'll try and explain
Firstly you can only do it from a normal browser and not from the app.
Go to availability, then length of stay. Click edit. Scroll to bottom and click add another requirement.
For during section, from drop down choose specific dates. Select the same start and end date that you don't want someone to check in on. Then set your minimum day, this can still be 1 night.
Then in the check in day, choose the day in front of the date you are picking. For example, if you choose a date on Tuesday, then check in day will be Monday.
This allows the room to be sold for the day, and a guest can check out on the day, or the guest can stay over the day, but it does not allow a guest to check in on this day.
Little long winded but great to be able to do it.
Just would be a lot easier if you could directly select to not allow check in on a certain date.
Hope this helps!
Ric