I don't have personal experience with this but very much doubt that it would work - if you just sign up for an individual policy and then try to make a claim for jaw surgery, they would most likely classify it as a preexisting condition and don't pay out. I am part of a Facebook group for jaw surgery patients in the UK, and only came across two cases where insurance paid: in one case a young person's parents' insurance somehow covered it, and another case company health insurance. UK surgeons I spoke to told me that private patients typically pay out of pocket.
