If you didn't get a voter card, you can get an electronic one by downloading the app. I did that and it was pretty painless. You still need to go to the polling station with a piece of ID but the app generates a bar code they scan and you're in and out of there pretty quick.
You don't need a voting card to vote. If you don't have a voting card, you need a piece of ID with your name and address. If you have your voting card, you just need something with your name.
I know, I was being cheeky with my question because I thought it was weird to tell people about an app to get a voter card when you don't need one to begin with.
Thank you for providing the information under my silliness. :)