I have recently acquired an SOS eCall fault along with a duff microphone (voice commands completely ignored).
Booked a service at Winchester for the eCall fault last week and was given this coming Saturday 17th April
Only discovered after that that the microphone was duff too so edited the service to include it and was given a new appointment for the following Saturday (24th).
Was hoping they'd contact me sooner and remote investigate and possibly even send a mobile ranger but not heard a proverbial squeak?
Ours cleared by itself after leaving the car parked for the day, no sentry. All other reboots/power downs etc (can't be 100% sure that latter was done properly) failed to clear our fault but didn't try the 12v disconnect. Additional symptoms of ours were no car visualisations and no GPS location updates.
Sounds like your happened long enough ago for it to have been left overnight etc. But if you use sentry, worth disabling that and leaving overnight. It probably won't fix the mic though.