Wylie, unfortunately I think you are correct that the tenants have all the rights to stay for the whole lease agreement. I was hoping that buying the place would break the existing agreement because it was not between the tenant and myself however advise shows otherwise. They may be willing to move out earlier, however as you stated I may have to compensate them to sweeten the deal.
I am going to try and avoid this otherwise I may have to find another property to purchase which would be a shame because the value in this area is going to increase. I am going to have a word with the real estate agent and find out if the current owner is prepared to discuss reducing the lease with the tenant so that I can satisfy FHOG and Stamp Duty concessions before signing the Contract of Sale.
The tenant has all the right to stay put, if they decide to do this there are plenty of other opportunities available.
Daniel