I believe the houses weren't sets but actual houses which C4 had purpose built for the show, so after the show had ended they were able to sell them off. But I'm not sure if this applies to all the buildings used like the bar, shops etc.
Two of the houses that are next door to each other are being used in hollyoaks, the dean family are in one house, and the couple who are about to get married are in the one next door.
However, only internal shots are used.