Zara Tindall and Mike Tindall attended a glitzy Champions Ball at the Dorchester Hotel over the weekend. The daughter of Princess Anne looked stylish in a Rebecca Vallance “Antoinette” puff-sleeve woven maxi dress. Meanwhile, her husband Mike, 46, sported a classic black tuxedo-style suit and bow tie. The relaxed couple enjoyed each other’s company at the prestigious London event. Held annually at the Dorchester Hotel, the Champions Ball is a charity event, which supports Rainbows Children’s Hospice, a hospice charity based in Loughborough. Typically, guests are treated to a champagne receptio…