Not sure what to do next, I have 40 villiagers cant get anymore than that as I keep getting a message saying there is not enough housing for more people and not sure how to get more as no more little scaffolding is appearing. I have done all of the puzzles and have all of the Tech upgrades. Have seen on the forums that others have many more villiagers but how do you get more houses built?

It sounds like you playing VV2 for iPhone, and not VV1. If you are, the maximum population for that game under normal conditions is 40 villagers. If twins or triplets are born when the population is near the maximum, you can get up to 42 villagers. There are no population bonuses for completing optional parts of the game. The messages from the desktop versions stating that there is a population bonus for completed collections were inadvertently left in and will be removed in the next game update.