When I turn the aircon on, the air from the vents is cool, but there is a noise that sounds like an extrememly pee-ed off wasp coming from drivers side in the engine bay.
^^ my guess as well, but mine's been like it for donkeys, & it's still sailing on - my wasp sounds faintly annoyed, though, rather than really p!55ed off! It might respond to some WD40 if you can get at it.
WD40 wouldn't help with that...!