Loud feedback noise on AirPods Pro during call

Just got a new pair of Air Pod Pro 1's. They connect fine via bluetooth and playing music through them from my phone is all good. However if I make a call, the recipient of the call just gets a very loud feedback noise. I have tried disconnecting them and reconnecting them but to no avail. Anyone have any ideas on how to fix this?

Thanks

[Re-Titled by Moderator]