"what is the procedure once you finish your hormone therapy"
Basically, you get on with your life!
I finished my HT 15 months ago, and I currently have my PSA checked every three months. I'm pondering whether to go to four.
I have been discharged from the oncology department, but they said they were happy to see me if my GP referred me back, and that has happened once, fortunately a groundless concern. I see my GP two or three times a year about other issues (mostly BP), and my PCa is always reviewed.
Plus, of course, like everyone else living with cancer, I look over my shoulder - we all know that cancer isn't behind every ache and pain, but we also know that it just might be behind the latest one - I never feel I'm wasting the NHS's time, because three minutes dealing with a concern is much cheaper for the taxpayer than mopping up afterwards (and I paid my share of taxes!).