Sub-Division delay

In 2003 we agreed to sell a piece of our land to close freinds for an agreed price. The deal was that the purchases carried the sub-division costs, land transfer costs, local body and council costs, engineering, sewage, the re-siting of a garage etc. It is now nearly three years down the track and we still have not got "Title" to the sub-Divided section. They have paid a deposit but the land has nearly doubled in value in three years. Do we have any redress.

Is there any written agreement? Normally if they don't follow through for such a long time, then you can in any case treat the agreement as having been breached. And end it.