Just an interesting update for folks starting out with the NHS system and not knowing what to expect:
I had my first appointment with a GP yesterday. It took quite a bit of time to get the required docs (official mail, my BRP-which isn't normal, but mine was messed up) so I could register, but once that happened, they were able to give me an appointment in about three weeks.
Was super worried as my meds are not licensed in the UK and alternatives are not covered by the NHS. Amazingly, though, I spoke with the GP and gave her my history (had printouts of medical history from US physicians), and she agreed I should try to stay on my existing medication. She's initiating what sounds like a rather long process to get 'named patient' permission from the NHS, but she didn't fight me on it AT ALL.
Very pleasantly surprised!
Will post an update as things progress, as I imagine this process will be a long one and hopefully of interest/benefit to other folks on thyroid meds!