Even when there is no will, the estate still has to be
administered, and the person taking on that task has to apply to the Probate Registry for "Letters of Administration". I know this because my half-brother died intestate, and it was a cousin who undertook that (assisted by an heir hunter company), because neither of his half-siblings were aware of his death.
The Bonavacantia List only lists new cases, and Heir Hunter companies keep their own records so that they can keep track, because there's no point in trying to open up a case that has already been solved by another company. Again, I know this happens, because Neil Fraser was able to tell me (from memory !) which company had dealt with my half-brother's case, even though it was 6 years previous (it wasn't F & F, incidentally). Neil has an amazing memory, which I suppose is a necessity of the job.
P.S. F & F have a huge range of records, but they also have something even more precious - experienced people out there in the streets, asking questions, because people can often tell you things that dusty old records can't
