You can give them appropriate notice 'For No Particular Reason'. It's your property, after all.
I wouldnt be using the 120 NTV... VCAT is cracking down on them and if the tenants take you there to dispute it then most times they are now being knocked back... especially if the tenants bring this issue up and saying that you are giving them notice as retaliation!
use the end of fixed term tenancy notice.
Furthermore dont use a notice if it isnt true... ie that you are moving in.... you cant release the property for 6 months after the notice has been served.. again if the tenants want to be ********s and they see it listed for rentafter they move out they can take you to the tribunal and seek compensation for moving costs