"took it in turns to run around the plane or swap seats and kick the back of my seat for 10 hours!!!"
If they were kickign your seat i would have informed 1, the adult they were with after informing the child to stop, i'd then inform the flight atendant and the issue would be resolved.
Worst case senareo shout at the kids adult and it will make the kid feel bad.
Regarding the runnign about, that's actually find it's encouraged on a plane to have a stroll up and down the cabin but if they were being a nuisance, then the flight attendant should have escorted them to their seats, turned the seatbelt sign on or informed the pilot of inappropriate activities in the cabin. I'm sure athletics is banned on aircrafts.
I had a child kicking my seat once.. Told them to stop they didn't, told him mum she needed to sort her kid out and just the act of me talking to his mum made him stop.