Hi Neil
as I view the Lexington Drive section from satellite imagery, it appears to be a solid painted line that divides the road. A solid painted line doesn't make it a divided road in an OSM sense. A divided road needs a physical barrier like a median strip or concrete barrier to be mapped separately in OSM.
See our wiki...
osm.wiki/Dual_carriageway
If it is only dived by the painted line still and not upgraded since the imagery then I can revert this part of the road edit if you like.

Hi
if there is a boundary marked by buoys in these waters you might like to map the buoys using the OpenSeaMap http://www.openseamap.org/index.php?id=openseamap&L=1
If the exclusion area is gazetted it may be possible to map in a similar way to habitat protected area to the south.
There is further info on the left side of the link under About OpenSeaMap.
I expect there is a specific way to map special areas that affect maritime users.
Initially you may like to map the buoy specifics and positions and add a description tag until you find out more.
I have found that the OpenStreetMap does not render all marine features.

Thanks for replying so promptly. I have added them back in now. Cheers.

not so, it just depends on the level of mapping for the area. For example; every building has an address in the Brisbane area due to the data being made available in a form suitable for osm and locally to me the house numbers have been mapped here.
osm.org/#map=17/-27.21779/153.02870
Mapping of houses often starts with house owners mapping their property addresses with or without the building footprint or with a note for other mappers to add. Later other individuals or teams of mappers may move systematically though suburbs or towns until data becomes available in a form suitable for import and becomes complete.
Here are sites near your edit that are mapped to that detail changeset/144568072#map=17/-37.79005/145.28719
changeset/144568072#map=17/-37.79092/145.37892
Some navigation apps only use osm data so adding the house address navigates to the particular house instead of just to the street.
If someone has gone to the effort of mapping something correctly it is best to leave that info in the osm.
A good read is the Good Practice guide OSM
osm.wiki/Good_practice
see point 10.2 in particular.

I have added tags that were on the tower as previously mapped to the building you added as an outline of the base.
I think the building tag around the base is not very suitable. The other transmission towers are tagged as nodes and I feel this is a better way to map them.
I have used the details below to add the tags you requested but don't know how correct they are.
https://overpass-api.de/achavi/?changeset=144498734

Hi
just checking why the house addresses were deleted for 3 Parker Drive and 14
Gallagher Crescent. Houses for these addresses can be seen in satellite imagery still and assume they were mapped so that people could find their house.

After referring to cinema website, I have shifted the node to the correct location.

Hi
You may have shifted the Palace Cinemas to a different location by accidentally dragging it’s node and it is now located in a carpark.
https://overpass-api.de/achavi/?changeset=144563156

Hi, there are also road section extending north that need renaming.

I added highway=tertiary to Diddillibah Road to allow it to render on the map and aligned with Esri imagery.

Mate, where has Diddilibah Road gone!
osm.org/#map=16/-26.6423/153.0358

Hi, I added a primary tag, office=company, reformatted phone and despammed description. You might like to change to a more specific primary tag.

I added a primary tag to your business edit so that osm can process what kind of thing you have added and render it on the map. You might like to change it to a more specific tag.

I added shop=tattoo to you business edit so that osm can process what you have offered and render it on the map.

You need to add a primary tag so osm can properly process your business details and render in the map…is office=company ok or do you prefer a more specific tag?

I added a primary tag so that osm can process what it is you are entering in to the database

Hi, you have entered the Steel Blue site twice in different places along the same street. Can you decide where the business is located and leave the details on the one correct node.
You accidentally removed the tag highway=residential from Irvine Street but I have fixed it.

Hi, we don’t use abbreviations in street names in osm … for example, St should be entered as Street

When mappers want to show the property boundaries, it is more common to map the fencelines instead of the plot of land as I have done.

Hi, houses are mapped by the footprint they occupy instead of the land plot.
I have fixed the tagging. You may wish to draw the building outlines accurately and put the address tags on the main building instead of the house node I added.