This is not necessarily true. In many parts of the country, you get a month free but otherwise the tax would need to be paid, which I guess is to cover landlord

This is not necessarily true. In many parts of the country, you get a month free but otherwise the tax would need to be paid, which I guess is to cover landlords who are between tenants. (saves some effort setting it all up and tearing it down again when it was only empty for a week or so). Also, you may not be able to claim that month if it has been claimed in the last year.