The link you supplied is probably legit in terms of them actually having what they are offering for sale.
There are probably 100s of small outfits, and an army of Indians on Freelancing sites selling email lists that do the rounds. One person probably bought them for a genuine list compiler like Duedil and from there it was re-sold and got into the hands of people who are essentially selling them in contravention of database rights, but its not easy to enforce.
In 2014 I bought a database of about 250 million Americans, many with DOB, race, religion, political aff, house purchase price, mortgage lender, mortgage financier, mortgage length, magazine subscriptions, whether they have AC or a swimming pool, net worth and a whole host of other details ... And is cost $250 or $500. I don't remember.
When I received it, I found it was data from the credit agency, Experian, obviously being sold without their consent. However, I couldn't care less, Experian are a disgusting outfit who have access to all sorts of info like your UK bank balances and this data is routinely sold for massive profits. They also have abysmal data protection, owing to their desire to make money over privacy; thus why an Indian who ends every other word with -ings is selling their data from a botched Joomla install with character encoding issues. They have also leaked something like 170 million social security numbers to fraudsters.
If you want to extricate yourselves from their dragnet, set up an account with Hang Seng bank in Hong Kong. Very cheap to use; and they have 86% capital reserves, as opposed to the 1% that UK banks likely hold.
