This green and pink calendar is run through availabilitycalendar.com
Its $15 per year per calendar. (So if you wanted one for Democracy house versus a separate one for Bruce Arms it would be $30
Its not the prettiest. But you can block dates very easily through their user interface,
I have set up a temp account with InnStyle.com who are a comprehensive booking system. Its 10GBP a month.
This covers full booking handling from the user requesting dates, through to paying for the stay. All the invoicing and reports and pretty much is comprehensive
It requires you to connect to Stripe for payments if you haven't already.
User sees something like this below