The agent or landlord can only inspect four times a year for normal inspections and then they have to give seven days written notice.
If they are showing the property to prospective tenants, they must give you notice that they are ending the tenancy, and then inspections require “reasonable” warning. Have a look HERE to see what applies to you.
Even if the landlord intends to end your tenancy at the end of the lease, they have to give you 30 days written notice of that intention before the lease runs out. If they don’t do that, and the lease expires, they then have to give you 90 days notice. This factsheet explains all that in greater detail.
Tenants and landlords alike will find most of their questions answered on the Tenants Union Website.