Rats

Maintenance

I have received an email today from a tenant who says she has rats in the garden. They have now found their way into the house and chewed dog accessories and eaten dog food which was kept in a bottom kitchen cupboard. She is wanting a rent reduction to replace chewed items?! We have identified a hole by a drain outside which we are filling as we assume that is the access. I am proposing to tell them to claim on their household insurance and advising them to keep dog food in an airtight container in a higher cupboard, is there anything else I am responsible for?