When the bike is idling I think the baffle in one of the stock cans is making a chirping noise, my mate says it can be heard from behind when i'm riding aswell, or could it be something more complex.
Can't think of anything in particular that could cause it?? silly suggestion..................you haven't got the alarm in service mode have you?? May sound daft, but these are the hardest type of problems to track down.
Have you checked that the exhausts are all firmly connected and mounted - could be the vibration causing a squeak where the downpipes meet the pipes to the cylinders ? Or if the baffle is loose - stick your finger down it ( when not running ) and see if it moves compared to the other one.
Just guessing really, but it does sound like something is moving or rubbing on something else - you can sometimes find it by letting the bike idle so its making the noise, then try pressing various bits of the exhaust and areas around it to see if it stops.