Commenters had raised the issue of proxy ballots, so as promised, I have investigated. Here's what I found (thanks to the office staff for their prompt assistance).
The law only allows a person to become a proxy for one other person; therefore no individual can go around and 'collect' proxy votes (the only exception being for immediate family members).
There were only 22 proxy ballots cast in the whole Montague council election.
This would seem to destroy any conspiracy theories; even if all those ballots were removed or changed, the outcome of the vote would be unaffected.
It seems therefore that the commenter in question is just someone who has his or her knife out for Ms. Coates - and I'm sure we all know who that might be. He / she might want to grow up and let it go now.
For those of you legitimately concerned, I hope the information above puts your minds at rest.