Tenants refusing to allow viewings during notice period

Tenancy Deposits

I have contacted them 3 days prior to viewings at resonable times one at 5.30pm during the week and another at 2pm on a Sat. Both are not convenient and they have said I have to wait until they move out. I have told them to refer to the contract agreement whereby viewings can be arranged during their notice. I am receiving abusive text messages constantly. Am I allowed to go in with keys to carry out viewings.

Also I have confirmed a checkout date on the 16th August at 10.00am they are now stating they wont move out until the 17th at 6.pm. They are signed to a periodic contract which commenced on the 17th of the month, therefore the tenancy runs out on the 16th. Would you please advise me how I should progress.

They also have a dog which I have not given permission to in the property.

Would you please advise me what action I should take. I do have a damage deposit which is in the RLA scheme.