I am going by what the rules said on the Poole website. Indoor mixing has different rules to sport events, where it seems to be decided by whoever is in charge or the council.
Edit - https://poole-speedway.com/ticket-office/code-of-conduct
Also if you could have any old 6 people sitting together, why does it say rule of 6 or 2 households?? If they mean six randoms then why have the 2 households it would contradict itself. More like it is 6 people from 2 different households which is what I thought. Seeing as apparently the council are thinking people broke their rules, that would make sense.