in which was a scale model of the rooms, used to plan the show -
bbc.co.uk/iplayer/episode/b01pqgt9/Countryfile_30_12_2012/. Hockney's part starts at the 25-minute mark, but before that you can watch items about the Brontes, Beatrix Potter, and a land sculpture north of Newcastle - and see panoramic and aerial views of some wonderful landscape.
Hockney uses the ipad for drawing because, as he says, it's the quickest way to quickly establish a range of colours. He talked about his habit of asking people, as they drove along, "What colour is the road?" - and how asking the question is important to the act of looking. "Every time you drive along it, the road is different."