This is mostly a good thing. The NHS is of course a huge trove of valuable information, but there are some incredibly compelling reasons to make it available to anyone who can improve patient care - start-ups should be interested in this too.
I'm more concerned about other forms of insurance, and about links to people related to you and not you personally. For example, what if people start getting a higher car insurance quote because someone in their household had an alcohol problem a few years ago? What if parents start getting refused life insurance because someone's sibling died young from an unlucky genetic problem?
Plus there are the obvious concerns if employers or their representatives/trade bodies can get hold of this kind of data and discriminate in dubious ways when making hiring decisions (sorry, we don't hire anyone who ever had a drug problem, even if they've been clean for a decade), media people going after celebrities/politicians/crime victims (that rape victim was obviously a slut, look at the two STIs she's had in the past five years), and so on.
It's only the commercial exploitation I'm worried about - it has a lot of potential to meaningfully impact human lives, usually for the worse, and often because of things said humans have no influence on.
Though for those living in totalitarian/fascist societies (e.g. gays in Putin's Russia) have much better reasons to be concerned.
Company execs are about the same way. So you earn 100K pounds per year and someone wants 1K pounds to keep something quiet that could derail your career. Well, OK then. As long as it doesn't scale to 100 people all trying to blackmail the same guy. Or if you could just sign this sale contract with our company, we'd have no reason to explain to our shareholders all about your mental health issues 30 years ago that obviously cost us the contract.
Thanks.