Re: About bloody time!
" I simply could not believe that I wasn't even required to prove that I had possession of the vote card that came through my door! "
For the very simple reason that margins in virtually every seat are such that unless a lot of personation is happening then it won't make a blind bit of difference to the results - and if it _is_ happening at that level then it invariably manifests sooner or later in the audits as multiple votes.
It's hard enough to get people out to vote. Any form of discouragement is counterproductuve. I have long-serving regional returning officers in my family and they assure me that there are random audits of polling stations and the electoral commissions in virtually every country _do_ investigate rumours of such things - bearing in mind that the chances of any conspiracy remaining secret rapidly approach zero as the number of people exceeds one.
The actual number of such rumours which are found to have substance is very low, vs someone boasting about multiple votes (1-2 every year, they get caught and get slapped around in courts), or stealing postal votes (which is _vastly_ different to polling booth fraud and happens to leave an evidence trail as postal votes are _not_ secret and are kept for a long period after the poll - precisely because of their susceptability to manipulation)
Even with that, the incidence of postal vote fraud is so low that it statistically never affects results - in a marginal or close result those votes are going to be _very_ closely scrutinised and any which seem to have the same handwriting are likely to come in for extra special attention (would-be fraudsters are never particularly smart about what they do - if you really want to game an election you do it by gerrymandering, voter bribes and flat out manipulation of the scrutineers or the counting mechanisms)