Yes, about a fortnight and starting gets very grunty.
Same with all the 'alarmed' fleet - only the unalarmed S2000 is a bit more durable. Well was; the battery is now ancient. I mean, really ancient.
Had a CTEK connection problem on the 86 and a relatively new battery was killed dead as I didn't realise. Generally, I get a good few years from batteries as the cars are effectively plug-ins.
You have to clean the CTEK plugs quite regularly - the contact area is rather small and oxidises quickly; the charger gets terribly confused.
I've also started to use cheaper batteries - I don't think Panachronic or Youass ones are anywhere near as durable as I thought they once were.