Working in the boat insurance industry, I can confirm that StolenBoats.org.uk does work, as a 5% recovery rate is far better than the situation 2 years ago before the site began. We have also seen a reduction in the numbers of boats being stolen. The short-comings of the Police National Computer has also meant that the police marine units will check this site for information rather than their own computers.
Thankfully the theft of narrowboats is rare and so there are only a few narrowboats listed. The owners of "Cragdale" should contact their insurers to get the boat listed, or alternatively send me the details, and I'll get it listed on the site.
If forum members think that it would also be useful to set up a separate category for narrowboats or inland waterways, let me know and I'll contact the site developers.
Jon