Don't know if this is any use to anyone, but a few years ago, I worked for the local council and managed to hear of a cushy job that not many people knew about, as it's usually council workers that do it. The job is being a "Polling Clerk" on election days. Basically, you have to be on the electoral roll to do it, and you can be a clerk or a polling officer. Officers are in charge of a polling station and clerks help them. The clerk job involves arriving at 6.30am and helping to set up a polling station. Men come with the heavy stuff and put it together, you sit there with an electoral roll for that ward and tick people's names off as they come in and give them a card to vote on. Then you drink tea, eat chocolate and read a book all day. You have to stay from 6am to 10pm at night until the box is taken away, you can't leave the building (but you can go to the toilet), and you have to take your own food or have it delivered. BUT, you get really good money for doing this - I got about ?53 (it is taxable unfortunately) which was a fortune in those days before minimum wage!! I covered local elections, I would have got ?87 for European ones. I also got paid my wages from the council on top of this as it was a "public duty". So in today's terms, you would be quids in!!
I think it is a good one off job to do, if you have someone willing to look after your kids in the morning and at night - it's only for one day!! The elections officer at your local council is the person to contact I think.