Yes, you can install a qualifying system on your own house under Navitron's EasyMCS. You will need Pub.Lia. Insurance £75, though. Give Tim or Cathy a call at Navitron HQ to get started.
Is the insurance the only cost, or are there associated fees - if so, roughly how much? Trying to work out how much it would cost to install an RHI-qualifying system myself...