Searching for UK based health farm (for want of better word) able to help with food addiction.

Previously happy, high achieving teenager is severely addicted to sugar, causing depression, behavioural issues, inability to attend/concentrate at school, general unhappiness. Only recently made the connection between the mood swings and the sugar but it is very evident and real. Looking for a place/health farm that might offer total safety from the everyday temptations and pressures of life (for perhaps a couple of weeks) so that she can kickstart a weaning process for this addiction, which is currently all consuming and destructive. She desperately wants to rediscover her stable, creative, fun, positive, upbeat, happy, healthy self.