My boss has not properly signed my AWA - does that make it binding?

Last year my employer introduced workplace contracts. I was happy to sign it at the time but since then the bosses partnership (business) has had some rough patches and work has become a less than nice place to be. One of the components of the contract was that due to loss of goodwill, I could not seek employment within a 15 km radius within a two year period of terminating employment. I was looking at my copy of the contract this week and have noticed 1. It is not dated and 2. The employers signatures do not have a signed witness (there is a gap but they never got a witness to sign). Is this contract a valid contract or do the absence of these two features make it just a worthless piece of paper? Am I eligible to take a job up the road as I feel I need to leave this job before it really gets ugly.