They were approved by the UK Financial Conduct Authority. That surely takes some serious legal effort and attention to detail.

Also, their About Us page suggests that they are staffed by people from relevant financial services companies. Plus they are backed by some VCs who would not take risks by handing money to a company if they thought the legal side wasn't up to par.

We don't know why there wasn't an annoying cookie popup. So assuming that the company in general plays "fast and loose" doesn't seem warranted.