I know there's a section of YouTubers who encourage fans to donate on livestreams or subscriptions through Patreon and platforms like that but usually it's nominal sums not hundreds of pounds by extremely vulnerable viewers. These YouTubers also tend to be new creators with minimal income accrued through their YouTube channels and for whom YouTube is their only revenue stream i.e. they don't have a cushy day job on ITV and their own production company. For those who are unfamiliar with YouTube's revenue model, there are a lot of creators who get their videos 'demonetised' for various reasons (content that is not family friendly, for example) and they won't make any advertising revenue from their content as a result. They might also put a lot of production value into their videos like paying guests, buying props, hiring an editor etc. Clearly none of these apply to Mark and Nadia's channel, it is minimal effort just filming what they would be doing anyway.
I appreciate many ordinary people help fund celebrities' lifestyles to an extent by buying concert/movie tickets and other merchandise but at least they're getting, for the most part, a tangible product as part of that exchange or at least something to watch with high production values rather than a middle-aged couple arguing over a stove a few times a week. With all of their apparent emphasis on mental health when it pertains to themselves and their children, you would think (or hope) they might have a modicum of concern for their vulnerable viewers who will be lucky to have 1/20th of their net worth and wonder how they can afford to bankroll them despite this clear difference in status.
For God's sake, even unscrupulous betting companies will send you emails and conduct checks into how you're funding your gambling if you start spending hundreds in one transaction yet these self-aggrandising imbeciles don't seem to care how their minions are sourcing these large donations!