Classic car but unreliable

Football
Fartlek
Tennis
Cycle to work
Semi- final heartbreak
Today decided to take the Audi to work as I haven’t used it for around a couple of weeks. And if you don’t use it for a couple of weeks, the battery goes flat (alarm I think). Just too late.
So, after work (close game of lunchtime football until the last 5 minutes when the opposition folded up like an origami swan), gave it a jump start from the reliable car.