I’ve been involved in a few local elections.
When an election is in the offing, a mail is sent round to the folks who work for the local authorities, asking if they want a days work at the polling station. They have to be there early in the morning (6am ish) to open up, have to stay on the premises all day, and then usually stay on to do the counting after polls close. It can mean working many many hours, especially if there is a recount. It’s possible to have to work all night on the count.
One of the group is made presiding officer. They get a slightly higher rate of pay, and they make the final decision about what happens in the polling station.
it’s really important to realise these folk aren’t kept in a cupboard and brought out just for elections. They are ordinary folk with ordinary jobs. In my experience most just want a quiet life. I’ve met some who really knew the rules - but in my experience most have had the briefest of training and it’s not unknown for the candidates and/or their agents to know the election rules much better. Even where there has been clear election malpractice ( such as one candidate driving onto election premises with their van festooned with election leaflets etc which is an absolute no no) , even when reported to the presiding officer, all too often no action is taken. It’s not surprising therefore that if there are issues, those folk, vulnerable and sat just behind a table, don’t want to risk their safety by challenging anyone.
So I wouldn’t be at all surprised that if there was malpractice, nothing was done about it at the time.
As for postal votes, absolutely they should be limited. They are much too easy to get at the moment. They offer far far too much scope for abuse.