I recently replaced the heater flap actuator with one I bought of Ali Express. It all seems to be working fine, and I think a lot easier than replacing the wheel inside.

Prices seem to fluctuate a bit, I paid £23, here's the link:

https://www.aliexpress.com/item/1005011771253263.html

Nice one, it would be easier than stripping down and refitting a disc, thanks for the link I have put it in my wish list in case mine packs up