I wrote about being lazy and pants at maths before but I've been playing with Firebase as well as having my many, many faults. I decided to turn my faults into positives though, and carried on with my lazy endeavour; the result is now up on github: https://github.com/annoyingmouse/archery-scorer. It's dead easy to run!
I've a list of Todos which I'll get around to as and when I've got time but in the meantime it works well enough for me and seems a better solution than paying for one of the dedicated mobile apps available for Android or though the Apple App Store. See: not only lazy but tight as well ;-)