My wife and I signed a land contract for a block of land off the plans. It has been over 12 months and since signing the contract our financial situation has changed. We have not been handed the title as yet. Also, the local government has changed the original plan of the stage with the developers, changing our dead end street into a through road. This was one of the reasons we bought the block, for the safety and quietness.
Are we able to end the contract of sale, and hopefully get back our 5% deposit?

Depending on the terms of your contract, normally you can walk away after giving some notice, but don't expect your down payment back,
A lot will depend on the exact terms of the contract.

I have sold dozens on contract and bought a few on them, I have never seen one where you get your down payment ( deposit back) that is how they make their money when you do walk away,
Of course since most require a 10 to 20 percent down payment you did not do too bad.