If you can live with it at least you will have an obstacle database. Ozrunways does not produce one, as far as I am aware at this stage, so your only option to get an up to date one is to get one from another source and AvPlan is one option but you will probably have to get a full subscription. I suspect at some stage someone has loaded it on your system to give you an obstacle database.
To find the files go to setup and load files and you can load an up to date file. Unfortunately I can’t recall if there is a delete option available there.