A landlord will deal with breaches of covenant by serving what is know as a section 146 notice on his tenant.
This notice warns the tenant that they are in breach of the terms of the lease. It cannot be used if the tenant has not paid the rent.
It tells the tenant that it is your intention to forfeit the lease and gives the tenant time to fix the breach.
If the lease is a long residential lease Ask a lawyer for specific advice as your tenant may have additional rights.