I've been involved in the medical industry (equipment etc) for many many years, and before that in the NHS.
Quite recently at a major and VERY expensive private hospital in London I found equipment that was seriously dangerous. The electrical isolation has been bypassed and everything was just plugged into an extension lead.
The private healthcare industry, by that I mean private hospitals etc, likes to portray itself as providing the very best medical care. In fact many are run on a shoestring. They need to make money so corners get cut. How many fully qualified and competent doctors are in a private hospital at say midnight ? The answer is probably zero. If you need a specialized investigation or treatment it is likely that the nurse also does many other jobs, he/she will not be specialized.
Almost any doctor can go into private practice. As soon as you get basic qualification as a doctor you can rent a room in Harley St. Private hospitals, generally do require that you work in the NHS, but that does not mean that you are a good doctor.
This is a private hospital. What happened here is sheer incompetence. Epididymal cysts are quite common, and a competent urologist would be aware of the possibility of mistaking the testis for the cyst. Do NOT believe the hype about private care being "the best". It isn't, you or the insurance company are paying for convenience, private rooms, staff being nice to you, and being generally shmoozed. You are not paying for superior healthcare or surgery. In fact as surgeons mainly get paid for carrying out operations, you could be paying for surgery that you do not actually need. If you are tempted by private healthcare, be careful.