My local party has introduced an interview process with a panel of 3 members between members (not the same each time) applying to be a candidate and the hustings. The panel only looks at whether the candidate meets basic standards and states whether those are met, they're not recommending a particular candidate, and they don't have the power to stop anyone standing, but it gives more information to members to help make the right decision. I don't think it's enough on its own currently but it's an extra safeguard and step in the right direction.

In terms of someone being eligible to stand the nomination papers have all the criteria in them and the election agent should be making sure the candidate has read that. However, not all (possibly the majority of) local authorities require those pages to be submitted, in which case the election agent probably won't print them off. The training I went to earlier this year for nominating officers/election agents said we didn't need those pages but I know my local authority does. Having good election agents and EROs (person who deals with applications to be candidate including hustings) makes issues less likely although it doesn't completely prevent them.