Hey mate I had a work colleague who has a better idea than me have a look today and he recons it's one of the bearings the belt sits on (AC compressor i think). I'm going to cover the belt and spray some white lithium grease in to the bearing he showed me in the morning to see if that quietens it up until I can get it replaced into the new year. Would that make sense as too why you can also hear it when it comes off boost because that's the most worrying part to me. It does that rattle/jingle everytime I change gears gaining speed and even with the windows up i can still bloody hear it.