Since I don't live in he UK, I can't answer your specific questions. That said, I have a question for you. Have you had the 24 hour PH monitor test to see the level of your reflux? That will be important information in answer to your question about singing again.
Many people who have hoarseness due to reflux experience a complete recovery of their larnyx. There are a few who are highly sensitive to small amounts of reflux who continue with some problems, which could possibly include persistent hoarseness. My guess from reading posts throughout the past 3 years I've been participating in this forum, that the odds are in your favor.
I would expect a really excellent ENT would be able to answer a lot of these questions for you. When you see your surgeon see if you can get a referral.
Think positively! Try not to start projecting negative outcomes into your future. There is a very strong mind-body connection, and if you can expect a good result, it can help your recovery and give your body a better chance to heal properly and more quickly.
Good luck with your appointment!
Words of wisdom by Eckhart Tolle:
"Whatever you fight, you strengthen, and what you resist, persists.”
“Worry pretends to be necessary but serves no useful purpose”
“Accept - then act. Whatever the present moment contains, accept it as if you had chosen it. Always work with it, not against it.”