I have just discovered that my excellent tenant is using the rental address as registered address for a 3rd party's companies (2 or 3). Am assuming this is for a friend who appears to be resident in Germany.  My tenant is not running a business and there are no nuisance issues so I am unsure of my position.  The tenancy agreement says no business can be run but the business is not run from the flat. The registered address shows clearly at Companies' House as been c/o my tenant.  As this situation is one step removed from the business being run from the flat , I am not sure if the Tenancy Agreement can be invoked, if my mortgage and insurance might be affected.  The tenant is excellent so I don't want to raise this if I am being over-worried.  Advice please, Sorry if this is filed in the wrong category.