I agree with the comments by rickathedj below and in another similar thread about SYNECA.
In the UK, there are a number of businesses that make money by tracing people to lost bank accounts and people who have died intestate. A 30% cut sounds about right considering the leg work they often have to do - and sometimes without finding heirs, or failing to sign them up, possibly coz another finding company has got there first.
It does not surprise me at all that they are operating out of a house. Why not? It's going to mostly be internet based or involve legwork on the road, neither of which need office premises.
In the UK there is a programme on TV called "Heir Hunters" all about this trade. You can see a whole episode at the url below free for the next 5 days. There are also plenty of details and clips, as well as a warning about scams.http://www.bbc.co.uk/programmes/b007nms5
You can of course try to check it out yourself as rickathedj did - and there's no harm in trying that, as you might save some considerable money, and if you find nothing, or it looks like being a lot of hard work with no certain outcome, then you still have the option available of taking up their 30% cut offer.
It's offered as "no win no fee" which is reassuring. They may well be 100% legit, but the way internet scams of many varieties can work is that they promise something free and hook you in...and all seems to be going well, and then they "hit a little snag" and just need a small amount of funds upfront in order to complete the deal or "need a small deposit to show you are serious" - this is the pattern of many scams including
(1) the Nigerian Bank Account scam which promises to let you keep a cut of funds that for some reason need to leave Nigeria and so they need to go to your account - but after a few communications it turns out the deal while possibly even more lucrative that initially thought, just needs a few hundred pounds for the documentation to establish the paperwork and legitimacy of your account (an ironic twist) and set up the transfers.
(2) the hot babe from Eastern Europe who after a few emails in broken English wants to come to your home locale to meet up with you - but alas she is a little short on the ticket price coz her grandmother has medical bills, and can you help her out?, coz she's so much looking forward to having fun with you.
I would also be careful to state to them in advance and in writing that your understanding of "no fee" means that you pay nothing if they are unsuccessful and only 30% IN TOTAL of whatever they ACTUALLY RECOVER i.e. not what you were left but the evidence shows never was their's to leave, or is legally supposed to be yours but in fact has "disappeared" or what is supposedly yours according to intestacy laws but is going to require a court battle to prize it out of the hands of another relative.
A number of cases (and many disappointments) have revolved around people discovering that there may well be "no fee" but they are still expected to pay disbursements, expenses and costs they incurred. Likewise is their 30% fee if they are successful their only charge? - or will they be adding everything else to their bill; photocopying, certificate charges, travel, subsistence etc.
When you inherit your multimillion pound estate, please put me down for a short all expenses paid holiday as your guest at your place :-)