Powerful property and farming firm Grosvenor Group says knock-on effect of Iran war could arrive next year Powerful property and farming firm Grosvenor Group says knock-on effect of Iran war could arrive next year Fertiliser shortages caused by the Iran war have driven up costs for UK farmers by up to 70% and will have a “dramatic” impact on food prices globally next year, according to one of Britain’s most powerful property and farming companies. Mark Preston, executive trustee of the 349-year-