Your round trip on 270 miles on round trip with a half decent EV eg one with a 250 mile range will mean that you're going to charge for around 20 minutes (actually about 5-10 mins will do it) on the way to the game or on the way home while you go for a wee and grab a sandwich. Will probably cost about £10 - £20 max. Your total journey will be about £22 max.