The Spice Girl, 52, and her husband Christian Horner, 51, wanted to shift their current boundary back from the road and install stone posts on either side, replacing the current timber set-up.
The singer, 52, beamed as she joined fellow celebrities at the lavish event at The Park Restaurant in London on Friday. She completed the outfit with some white heels.
The girl-group are understood to be considering a reunion of their own, six years after they filled stadiums across the United Kingdom with their Spice World mini-tour.