Thanks for your time replying
Some generic tips that seems like the next thing to do. Even though it is hard to say, it seems like the usual suspects around the belt (alternator, pumps) are not the guilty ones this time. I'll try to do some more directed listening but I prefer using a wooden stick instead of a big beefy screwdriver...
Also booked a time with my old trusty mechanics a few weeks form now. Just in case.