Tenant has dog without permission, can I enter to investigate?

Access

Hi,

I saw one of my tenants leaving our HMO with a dog (she's also being evicted at the end of tis months for rent arrears). I queried why she had a dog and she said it was her boyfriends and it didn't live with her. I explained that pets were not permitted and that I didn't expect to see it here again. The cleaner sent me a message today to say that she could hear a dog barking in her room. Our managing agent has advised that all we can do is send her a reminder of her lease and inform her that she is breaching her tenancy agreement.

Am I able to ask her directly to remove the dog? Also, if I knocked on her room and she didn't answer could I enter the room to see if the dog has been left unattended?... the dog looked well so I don't know if I'm able to involve the RSPCA?

Grateful for any advice.
Thanks in advance.