Hi. I've a 2016 Micra (K13) 1.2 (80) N-tec CVT which I've owned since August 2019. It's a one owner, full Nissan service history vehicle with 25K miles on the clock. I noticed it was making a "chirruping" noise from the engine on startup and acceleration. I took it into the local Nissan main dealer who fitted a new alternator belt (seems a bit soon to get alternator belt problems at 25K miles but it is over 3 years old?). The cambelt is a chain. All was fine until about a fortnight after when intermittent "chirruping", the same noise as before, started again. I booked it back in to the same Nissan main dealer who advised that all was good with the alternator belt and that the tension was correct and advised against increasing the tension since it could affect the life of the belt. The "chirruping" only presented slightly and they said bring it back in if it gets worse. The trouble is that whilst the "chirriping" is still there, I can't produce it on demand! Anyone any ideas what it might be taking into account that all seems good with the alternator belt? Thank you!
If I'm thinking of the right sound, it may just be the belts flapping - a design flaw with the engine not a maintenance issue

Does it happen more while cold than while hot? Does it have airconditioning or anything else drawing a lot of power that may put a load on the accessory belts?
It happens when cold and hot. A strange thing I have noticed is that it can sometimes happen when steering for example round a roundabout. It does have climate control, sat nav, hardwired front and rear dashcams together with a hardwired DAB Adapter?