Vacant Possession

The new APT from TfP has a heading

This tenancy agreement is subject to any existing tenant and/or, any other occupiers, vacating the Property and the Property still being available to let, for example, including but not limited to, being damaged by fire or flood. For the avoidance of doubt in any of these circumstances this tenancy agreement will not take effect.

Which means my earlier concern about not having the landlord ‘enter into’ the agreement before getting vacant possession is bypassed.

You can have everyone sign as soon as is convenient, receive the rent and then if previous tenants don’t move out… the new agreement does not take effect.