Interesting statistics from BARB.
From 1956 to 1960 the number of TV homes rose from 5.7 million to 11million. The next 10 years had a steady yearly increase until most homes had a TV by 1970. In those 10 years around 4.5 million extra homes had a TV, some would have had 2 TV's.
Those numbers show the saturation that the late 1950's had for the TV market.
http://www.barb.co.uk/resources/tv-ownership/