Hi all, I am new to this site so apologies if this is in the wrong thread or place.

So I have an automatic mini r56 (07 plate) which I have had for a year and a half. Around Christmas time I started to notice that it was making a bit of a whining noise when accelerating and decelerating sometimes. It is mainly from 0 to 30 where it was happening most, I did some research online and a lot of people mentioned transmission fluid change so I got that done as it hadn't been done previously. Had 90k miles on the the clock when I bought it and has 97k now, that didn't change anything or help. I also noticed that noise smooths out once it gets to 30 and you can hear it smooth out and get quieter. The noise is also there when in park and revving, I also had a fault for intake manifold unmetered air which we have solved as my dad's friend is a mechanic and we got this sorted, the Crank case breather pipe hose had split into 2 and also the rocker cover underneath was completed blocked and the diaphragm was broke. That's all been sorted and the code went away and hasn't come back, my dad's friend thinks that the noise is most likely a faulty alternator bearing and I have read online that it could be a worn pulley or belt which might explain the noise? I have also noticed that it feels like a bit of power has been lost slightly and especially the pickup from stationary. Would an alternator bearing cause this or could it be a clutch issue? I have also read about a torque converter but its hard to know what to beleive and something that big surely there would be a bigger problem or sign? My dad's friend is doing a service in the next week so he will do some diagnostic checks and see what he can find, he hasn't worked on many minis before and I just wondered if anyone can offer any other suggestions as to what this issue could be and what common things to check for and rule out? Any suggestions would be much appreciated... Thank you!