As a landlord your rights and responsibilities will be laid out in the tenancy agreement. Detailed below is some information which may not necessarily be covered in the tenancy agreement but are a matter of good practice.
You have a right to enter your property to inspect the state of repair for example, but you must ask the tenants permission first and give them at least 24 hours notice. The only exception is where there is an emergency (e.g. gas leak or fire) and immediate access is required to avert damage or injury. You do not have a right to enter in any other circumstances unless you have a court order.
It is in your interest as a landlord to inspect the property on a regular basis to ensure everything is in good condition. A regular inspection every 3 months should be sufficient, making tenants aware of this fact before they sign the tenancy agreement is a good idea.
If a tenant refuses a landlord entry to the property then we would advise the landlord to seek legal advice immediately.