By Tony Jimenez GULLANE, Scotland, July 18 (Reuters) - Phil Mickelson was more than mildly irritated by the army of helpers and officials allowed inside the ropes during his opening two-under 69 in the British Open first round at Muirfield on Thursday. The American left-hander, bidding for a rare back-to-back double after winning the Scottish Open crown at Inverness last week, bemoaned the difference in organisational style between Europe and the United States. "It's a different culture over here," Mickelson told reporters on another sun-baked day on the east coast of Scotland. ... More...