Volkswagen Golf - Golf 2.0 TDI screeching sound - belt/pully wheels? - K21000

I have this sound which has been getting worse for a couple of months, most noticable on idle. It seemed to go once up to speed, but I have heard it more intermittently. Just pulling up tonight it was worse and I could smell burning. I also noticed engine idle revs went up 200rpm which has never happened before. I turned the engine off and restarted and the idle revs were back to normal. I am going to park it up and use my daughters car. It sounds like it's coming from the alternator area. Car starts ok and holds a charge. Any ideas appreciated. It's an old MK5 2.0 GT TDI. Below is a vid of the noise, but it has sounded worse!

https://www.amazon.co.uk/clouddrive/share/yg1pYlPXT4nsq2mDZOwtxviKE9PiOz3FdjIt363OW9X?v=grid&ref_=cd_ph_share_link_copy

Volkswagen Golf - Golf 2.0 TDI screeching sound - belt/pully wheels? - elekie&a/c doctor
Sounds like the alternator pulley is in trouble.not uncommon on these .These have a clutch drive pulley that eventually starts slipping after so many years.
Volkswagen Golf - Golf 2.0 TDI screeching sound - belt/pully wheels? - K21000

elekie&a/cc doctor, you were bang on. Thanks for your advice!

Volkswagen Golf - Golf 2.0 TDI screeching sound - belt/pully wheels? - Steveieb
Well done again Elecie doc. My indie was able to replace the clutch mechanism rather than the whole alternator saving me over 100 pounds.