Especially as we reckon there were a lot more people who would have signed the petition, but for the rule that only one person can vote from the same computer.

For example, my wife tried to sign the petition from our home PC but couldn't, because the govt checks the IP address to prevent spammers block voting. But doing this prevents a lot of legitimate users from signing too.

So you could probably assume a lot more people (prevented from signing the petition) could be added to the total number of people who won't vote for Labour next time.