I managed to get call reports working, I built a little api using python in google cloud which process the information that vapi sends, this emails me a report and adds a row to a google sheet every time a call completes.
To switch it on, easiest way is just to add a webhook you create as sever url in the 'org settings' part of the vapi dashboard. Probably easiest to do create a webhook if that's unfamiliar to you is in make.com or something.