It's an objective view, this is a forum for discussion. Investing in a flat to start a family, funny if that was your priority perhaps you should have been more wise whilst purchasing a home. Through your nievity at best, stupidity at worst you have purchased a flat that you now cannot complete on, and will have to pay the financial penalty!
GOOD LUCK in not getting sued, however if i were the builders, i would be looking to exercise my legal rights laid down within the exchange contract!
Shanks