So farewell Countdown (Channel 4) – at least, as we have known it for many years. The programme will reappear in January but without Carol Vorderman – and Des O’Connor. On last Friday’s show, which was the 59th final of the contest, Carol bid a tearful farewell to the series. The tears were understandable, as Carol was saying goodbye to a programme she has appeared on for 26 years – not to mention bidding farewell to the near-million pounds she was reportedly getting for 40 days’ work per year: doing sums and picking out letters of the alphabet.

One Last Consonant Please, Carol (Channel 4) retraced her time with the programme, from the day in 1982 when her mother forged Carol’s signature to get her accepted for Countdown; through 4,750 shows – often with Carol wearing woefully unsuitable clothes; and the numerous gaffes created by her co-presenter Richard Whiteley.

The tribute to Carol Vorderman was introduced (and in danger of being monopolised) by Gyles Brandreth. Carol described Brandreth as appearing on the show from its earliest broadcasts: “In those days he was probably the most irritating man in the world who wore jumpers,” adding: “One of those things has changed.” At least Gyles often used to talk about words when he was on the words-and-numbers quiz, but later guests simply told showbiz anecdotes which were irrelevant to the theme of the programme.

Countdown follows such a set format that the director could probably do it in his sleep. Some people can do remarkable things while they are asleep. Sleep Walkers: Secrets of the Night (ITV1) introduced us to four somnambulists. Nine-year-old Olivia sleep-walks and plays games during the night. Xanthe makes herself meals in her sleep (and worries about the weight-gain so caused), while Lee says he draws pictures even though he is asleep. And Tim suffers from sexsominia, which annoys his wife Amanda because it is a condition in which sleeping men (or women) try to have sex with their partners. It is allegedly a condition that affects about 100,000 people in Britain. The programme set up night-vision cameras to film all these people. Lee didn’t draw any pictures while the camera was watching him, so perhaps he didn’t have the gift he claims, but the other three all acted as described. Yet the programme was disappointingly inconclusive: arriving at no definite explanations or solutions for their problems.

BBC4 has recently been showing absorbing programmes about Italian art, including worthwhile documentaries by Andrew Graham-Dixon about Vasari and the Medicis. The Perfect House: The Life and Work of Andrea Palladio (BBC4) celebrated the 500th anniversary of the birth of the Italian architect whose ideas were so influential that he gave rise to a whole genre of neo-classical or “Palladian” buildings. Trained as a stonemason, he was inspired by visiting Roman ruins to devise his architectural system which stressed proportion and symmetry as well as the classical ‘five orders’.

This system was fixed in stone by his many buildings, not only the great buildings in Vicenza and the church of Il Redentore in Venice, but also the villas he designed for rich clients in the Veneto. These country houses combined classical grandeur with homely intimacy. As one observer noted: “He liked architecture to make you feel good” – rather different from many of the buildings erected nowadays. This programme was educational as well as being a delight to watch.

One of the finest Palladian buildings near Oxfordshire is Stowe House, which was described by Niall Ferguson in his useful series The Ascent of Money (Channel 4) as an early example of the instability of the property market. The second Duke of Buckingham spent immense sums of money on Stowe, especially to impress the visiting Queen Victoria. The Duke thus built up huge debts and, in 1848, he had to sell many of the contents and move to rented accommodation. Plus ça change . . .