"There is nothing more attractive than a man who is not a New Man"

This quote by Jilly Cooper is referring to the idea of the "New Man" which is a term used to describe a man who is more in touch with his emotions and is more willing to handle generally female roles such as child care and housework. Cooper is recommending that there is something more appealing about a man who is not a New Man, and instead is more conventional in his gender functions. This could be translated as Cooper believing that there is something more attractive about a guy who is more manly and standard in his roles. She may also be recommending that there is something appealing about a man who is not scared to handle typically male roles such as offering the household and being the head of the home. Ultimately, Cooper is suggesting that there is something more attractive about a man who is not a New Man and is more standard in his gender roles.