I'm assuming you're referring to nomination papers, completed by candidates and submitted to the Returning Officer. It is the responsibility of the Returning Officer to determine whether candidates are qualified to stand for election. Provided they are so qualified, the decision (if there are more candidates than vacant places for election) is entirely down to the electorate. If there are no more qualified candidates than vacant places, then all those candidates are automatically elected without a poll. Nobody else has any formal role in the selection. Anyone, including the parish council, can invite candidates to speak on a public platform to put forward their merits, but candidates are not obliged to attend such a hustings. It would indeed be inappropriate to have the parish council "interview" candidates.