If she is running a business she has to register the business name and file taxes every year. They show up on this site. Here's Zoe as an example. https://beta.companieshouse.gov.uk/search/officers?q=Zoe+suggYeah she means her channel
Has she not filed any taxes? We know she must be doing alright, so it would definitely be illegal not to!
No sign of Brogan having any businesses.