Santander Cycles day pass

saajan_12

The new(ish) day pass for Santander cycles is working quite well when there's a sunny couple of days, as it can cover essentially 1.5 day commute if you can be a bit flexible with times. Ride to work day 1, from work day 1, ride to work day 2 if you leave slightly earlier ie within 24 hours of when you picked up the first bike. 

So far I'm being very cautious with this, allowing plenty of time to complete the last journey within the 24 hours. However does anyone know at what point it would start charging if say you started a ride just before the 24 hours were up, but finished it after? Does it let you complete a <60 min ride if you've started, or treat it as a single journey even if its just finishing a ride a few minutes over? Can't tell either way from the TFL pages which seem pretty vague.