
My husband is a clinical hypnotherapist. He says that anyone that practices in hypnotherapy should be able to show their qualifications and that you can check their website for details of which professional bodies they belong to. Membership of a professional body will prove qualification and insurance. Their details will be listed on the website of that professional body. There are a number of professional bodies to look for, including General Hypnotherapy Register and Hypnotherapy Society.
Any hynotherapist should be able to help with a general phobia of hospitals, but there are others who are specialise and are trained in treatments without anaesthetics etc.
Hypnotherapy does work for a range of things. I have used it myself for confidence building before stressful situations such as job interviews. I've also used it to help build my confidence before important shows, for example Crufts - I am a nervous handler. I think it helps to have a hubby who understands basic ring procedure! I haven't used it for weight control though, as anyone who's met me will testify. :-)