Proceeding to the second round:
I acquired a second-hand, genuine microphone from eBay, which came yesterday. With the sun shining, I seized the opportunity to replace the microphone; however, the space is somewhat limited. Procedure:
Detach the vanity light
Sever
Eliminate Gently remove the microphone cover by applying pressure from the rear to slightly detach it from the headliner, then detach the cover.
As previously said, it will escape into the netherworld if given the opportunity, hence it should be covered.
The microphone is secured with an exceptionally adhesive backing.
I used a plastic trim remover to insert it slightly, while simultaneously placing two fingers into the aperture left by the vanity mirror and rolling upward from the base.
Continue manipulating the tape/cover until the microphone detaches. It takes time, but it ultimately becomes available.
Carefully extract the microphone via the aperture and unplug it.
Ensure that you have detached the lid and the paper/filter component from the new microphone.
Reinsert and secure it in the opening.
Align it properly and use some of the adhesive if possible (I succeeded in tucking it below).
Reattach the cover, reconnect, and reinstall the vanity light.
Bob is your aunt or a similar relative.
It seems that my problem may have been resolved, as two individuals have informed me that the call was "significantly improved." I am optimistic.
I hope my instruction will assist others; it took around 25 minutes and cost £20 for the component, making it a worthwhile effort.