One of the joys of working in the public sector is that all your business is done in the public domain. Every single expense payment and category for many public bodies is available in the public domain.
In this particular case, I've no interest in exposing any particular individual. If Chris does identify the hospital, I'll write to the Chairman asking if any surgeons have retired and been rehired. If I don't get the information, I'll submit an FOI request. If Chris's story doesn't hold up, I know he'll be honourable enough to cover the cost of the FOI request.