<b><b>It is becoming ever harder to predict what sort of people want to buy into a particular development. So developers need to be flexible if they are going to be able to supply customers with exactly what they want. Stephen Hoare looks at the dilemma</b></b><br><b>Never has there been a more confusing time to read the property market. We are supposed to be on the verge of a downturn yet a low interest rate and the high returns on investment in property are pushing house prices ever higher. At the same time developers are finding that their middle market - the bog standard three and four bed detached house on a greenfield site - is no longer the safe bet it once was. </b><br><b>Instead, the clever money is on singles, young professional couples, divorcees, and empty nesters - because these groups have the means and the motivation to trade property and are likely to demand quality and location in a new home. This is not to say families do not buy homes, but their importance as a customer group may be exaggerated. A senior marketing director commented: &amp;“Sales brochures are still full of pictures of the husband, wife, 2.4 children and …