Hi Scott,
I had a quick look at this excellent site provided by the Land and Property Management Authority
SIX Viewer | Land and Property Management Authority
Put in your Lot and DP number in the "Take me to" section and make sure the "cadastrel features" box is ticked in the "Show Themes" section.
It looks to me as if the access to each property is within each of the titles and there is no evidence of a reserve for Lanhams road.
Unless there is a covenent preventing it I don't see why you can't fence your property at the boundary.
The solicitor should have the answer.

