The Travel Editor replies: There is a directory - which is basically a brochure - issued by a body called the Federation of Britain's Leading Health Farms, which will include all the major spa centres in the country. You can get a free copy (tel: 0990 667722) and leave your name and address on the voice-mail, assuming the system is working better than when I tried calling the number. Unfortunately, there is not to my knowledge any independent guidebook to the relative merits of the different spas and health farms. Even Holiday? Which has not covered the subject in recent years.