Outside the Château de Gudanes, a masterpiece of Parisian elegance tucked into the Pyrenees, is a work van with carpentry tools overflowing from the back tray. Poppies and cornflowers fleck the long grasses on either side of the gravel driveway, the copper-green patina of its shutters luminous in the afternoon light. Mountain pastures soar behind its mansard roof. But the van is a reminder: here, there are men (and one very determined woman) at work.

Ten years ago, almost on a whim, Perth-based Karina and Craig Waters purchased the 94-room château as a ruin that was also classified as a monument historique, with the same level of protection as the Eiffel Tower. They saw only the four main rooms on the ground floor before deciding to buy the property. The rest of the château was inaccessible because much of it had collapsed.