Having worked with Venn for years on all kinds of building extensions and conversions, Mackintosh was happy to delegate many design decisions to him. At the same time, Johnston was coming up with bright ideas, such as placing very large windows at the back where the house is hard up against the dripping, ferny cliff. The previous house had had an almost blank wall at the back. But in the morning, shafts of sunlight penetrate this mysterious gorge where water drips into a newly-made pool. Mackintosh insisted on a high-level bridge taking you across this gorge from the top of the tower to the land behind, thus to the bothy and over the hill to the estate villages and beyond. So the back of the house is as important as the front.

For guidance, Mackintosh and his team looked to the work of a great Arts and Crafts architect, Sir Robert Lorimer. Lorimer was to Scotland what the better-known Sir Edwin Lutyens was to England. More to the point, he had restored and extended several Scottish castles in late Victorian and Edwardian times. "Generally, whenever we had a problem, Lorimer had a solution" says Venn. Not that the house directly mimics any of his buildings, but it picks up on some of his tricks - particularly the way the south wing- containing living room and Mackintosh's bedroom - is joined by a low entrance porch to the round tower. Lorimer's work on Dunderave Castle, just before the First World War, gave the clue. But Mackintosh found inspiration in some further-flung places, too. The idea for the projecting front dining area between two splayed buttresses, he says, came from an island monastery in Croatia.