Saphire, welcome (long time no talk!) and thanks for posting.
In the four years since we started this community, we have unfortunately witnessed some scary stories. I've not read about a cervical disc slipping and blocking an airway, but some fusion patients have seen BMP overgrowth causing some serious complications. Their stories are on this board. And this board is just a small microcosm of what happens in spinal arthroplasty, so some of these "scary" stories may be true. Be a detective! Track them down for authenticity!
For a list of reasons, cervical ADR seems to have better results than lumbar ADR -- across a variety of artificial discs, patients and doctors. That said, cervical ADR and fusion patients seem to do well -- I have several friends that had cervical fusion and they are doing well after many years.
Did you review qualification and disqualification criteria for ADR with your consultant? They are different for each artificial disc -- which artificial disc are you expecting?
As one of your UK colleagues (Alastair) often said, "We are here to help!"