The problem particulalry of Polanski is that he is a party leader, not just a member, even a Parliamentary elected member, but a party leader. In his case he is someone who has come from nowhere to somewhere in a very short period.
Polanski's particular weakness is to pretend to be what he is not, to claim experiences he hasn't had, and while there are plenty of criminals and wife beaters among our MPs, there is a particular distaste for those who pretend to be what they are not, to have experience they have not had, it brings them too close to being, in modern terms, scammers, and people who do that tend to find themselves very rapidly on the outside looking in.
I would no more vote for a party led by a Polanski than I would vote for a party led by a Farage. Keir Starmer is, at least, just a plain old fashoned, power grabber and like so many such, he is determined to keep his grasp on power no matter how much his party and the electorate want him to go. With Starmer we know what he is - and he is just one of many similar leaders, Trump, Putin, That bloke in Turkey. Thankfully for us, the means of unwinding those grasping fingers can be done fairly easily in this country, much as they did in Hungary, but a leader who lies continually about his past, claiming expereinces and employers he did not have, a compulsive liar, that is a very different thing, and is always pushed to the margins - except in the Green party.
Badenoch and Ed Davey, as fas I know, they have never claimed to be anything they are not. Nor has any leader of any large party in recent history.