Ayda Field admitted it is a “challenge” carving out alone time with husband Robbie Williams. The couple – who are parents to Teddy, 11, Charlie, nine, Coco, five, and four-year-old Beau – think it is important to make space in their schedules to spend quality time together without their brood, but it isn’t always easy. She told Britain’s HELLO! magazine: “We went out for a date night recently and we don’t get to do that often so it was really nice. “It usually involves Rob and I having dinner or I go to his shows when the kids are asleep – even though there are 80,000 people there, it’s just u…