Help with a Conflict of Interest

Letting Agents

I have let out my property to the daughter of the letting agency that is managing my property. All was well until the rent became an issue due to lockdown etc. There is also an issue regarding repair work needed for a water leak that occurred at the flat. We are wanting to give notice and have given notice to evict the tenants and the letting agency have said it can be seen a RETALIATORY EVICTION which it is not, we just want them out and sack the letting agency. The tenants now know that as soon as the repairs are done they will be given notice and are now dragging out the which were once most urgent repairs. They keep coming up with excuses of not being available or that a child is ill and they are having to isolate etc...How do I get them out of my property as I am having to deal with the agency official route as well as the tenant who they covertly backing up!!😩 I am happy to clarify any additional information