Iran’s chief negotiator in nuclear talks with world powers in Vienna, Ali Bagheri Kani, returned to the Austrian capital on Wednesday morning after consultations in Tehran, Iranian semi-official ISNA news agency reported on Wednesday. The 2015 deal that lifted sanctions on Iran in return for curbs on its nuclear programme is within touching distance of being restored after eleven months of talks. But the negotiations have been complicated by a last-minute demand from Russia for guarantees from the US that Western sanctions targeting Moscow over its invasion of Ukraine would not affect its busi…