I would like to add some things to this topic and I know Shirley wont mind me doing so.
Whilst she is correct that many HH firms will be registered with the ICO some are not and this does not detract from what they do. It is a contentious subject has to whether we need to register with the ICO and whilst I am in favour of it I can see the arguments and understand them that we do not have to register.
In regards to the question has to whether we are genealogists or heir hunters. Heir Hunters is a term given to our profession by the media and not one we would use ourselves. We are genealogists who specialise in Probate. The distinction that needs to be made is between what people see as genealogy and family history. Genealogy is the science of studying family roots and Family history is the study of the history of the family. I am both has I carry out both types of work all be it now primarially I am a probate genealogist. Some firms consider themselves to be forensic genealogists. I hope that clarifies the genealogist tag :)
Shirley mentioned the Heir Hunter Association and whilst what she says is correct people should also be aware that many of us including the bigger firms will not join this association. By not joining does not diminish what we do. There are no professional bodies like solicitors have and HHA cannot guarantee their members are up to the job of doing this work. Many are I should add.
What I would say is take your time before signing anything with anyone who contacts you, seek legal advice if you wish but overall ask questions. The genuine people will answer those questions to the best of their knowledge and will always be open and honest. Dont though expect them to name the deceased until you sign an agreement because they do have to protect the investment they have made in time prior to contacting you. Again some will and in many cases where it is close kin that have died they will.
One final point is to do a web search of these companies that contact you. See if there is any negative press related to the company.