Think carefully before going against a doctor's advice. Yes, you can pay Thai doctor's to do what you want, but it doesn't mean it's the best choice.
As someone else said, surgery is a last resort. If your UK doctor has not recommended it, either continue with the prescribed medicine or talk it over with the/a doctor and see if he can recommend something non-invasive.
My prostate ballooned so I visited two hospitals (1st and 2nd opinion). My biggest fear was prostate cancer, but that checked out fine. Both doctors prescribed medicine and it has seemed to work as the "stream" is stronger.
Thai doctors will often do whatever costs you the most, so please don't demand something a good doctor has not recommended.