Complex sentence: When his wife left him and their children in 1985, he decided that he needed to work at home to be with his children, and placed an advertisement in "Private Eye" magazine: "19th-and 20th-century fakes for £240".
Split into simpler sentences: When his wife left him and the children in 1985, he decided he must be able to work at home to be with his children. So he placed an ad to Private Eye magazine- "19th-and 20th-century fakes for £240".