now I see your same car as me, I have this time to time and never got to bottom of it.
im fairly modified so a lot of things it could be from my mods but the part you say right in front of driver sounds familiar.
I have to coast down a fairly steep hill for a few miles then get onto a slip road so the first bit of revs/load acceleration my car does this and I was suspecting aux belt or cambelt/idlers etc.
got the cambelt done and did the aux belt myself, found nothing suspect and still continued after belts.
I have settled on thinking its from the hp fuel pump area and as pressure rises that first time it sqeeks a bit and then usually disappears for the rest of the journey, does the same return commute but road conditions different so loaded from right out of the works gate, it sqeeks each acceleration for a few times through gears then disappears again.
I had ruled out any alternator issue just as it follows load rather than run time.
I nearly never have aircon on so again I don't think that's my sqeek.
I also modified my turbo and intercooler so the only other suspect was a leak from exhaust manifold or turbo flange that sqeeks a bit when cold then seals up when hot.
but as you say seems to be vitually under windscreen end of r/h side opposite side to exhast/turbo.
if I am idling to warm up a bit before setting off I either don't hear it or it occurs closer to home.
I started to datalog loads of things when I was worried about mine , lots of parameters checked at time of sqeek and nothing significantly changed enough to be able to diagnose, boost, fuel pressure, swirl flaps(which I now don't have ,but still does it),egr(which I don't have)etc
