The Queen's granddaughter and her rugby star boyfriend bought the five bedroom Gloucestershire mansion in April, and have spent another £250,000 renovating it.
Pals say the couple "can't wait" to move into the three storey Georgian house, which has a large kitchen and garden - but no stables for Zara's 14 horses.
Twenty-six-year-old Zara and Mike – who have been living in a two-bedroom cottage on Princess Anne's Gatcombe Park estate for almost three years – have been house hunting for months.
Mike received a three-year driving ban in January and found it difficult to commute to his club. The new house is about ten miles from his team's Kingsholm ground.
Royal watchers see the investment as the clearest indicator yet the couple, who began dating in 2003, will tie the knot.