Accept that the therapist will not want or be able to make a proper assessment on the phone as to number of sessions, total cost, etc. If you are anxious, ask if you can take a friend along for the initial consultation. The first requirements in a therapist are competence and adequate professional training. Almost as important are the therapist's personality and character. You must trust and feel comfortable with a therapist with whom you may well discuss personal and sensitive areas of your life.
Doors banging and people shouting can be very disruptive during sessions.
Have a look at the diplomas on the wall to confirm the therapist's qualifications. Is a professional indemnity insurance certificate displayed or available. Now is the time to ask if you have any queries about these points. Make sure that you understand how much you are expected to pay per session and what exactly you are paying for. At the initial assessment or subsequent session the therapist may take a detailed history of your case, of past and current treatments and of any more general matters that may be relevant.