Within the contract you will have a date.
Your solicitor can on this date advise that you are ready to complete - knowing that they are not able to do so.
At this stage you are then able to either agree to continue with the contract or come out of it.
We visited the solicitor this week who explained various options available to us, however we still intend to buy as we believe long term the site will be a great place to live and a good investment.
If you look at the houses available both on this site and others, the site is good value for money, however individual circumstances will determin what individuals do.