Actually, Kennet District Council offers an excellent service for eradicating rats from domestic properties for just £36.

Is it a domestic property? For sure, since many use it as such on a temporary basis, and NT has no notice up prohibiting such use. I'd say it has the legal status of a holiday cottage provided for general use by NT.

As such, any current tenant could get the council out to it and ask them to invoice the landlord.