Do we buy the tooling as good as it is, and will it be able to cope Ok under NC circumstances or do we look for bigger and better?
Again I don't know much about lathe work, but presume 12mm tooling will be fine under CNC conditions
12mm will be OK. The beauty of CNC is that it is easy to take lots of shallow, fast cuts as opposed to a deep, slow roughing cut.
If you don't already have a QC toolpost, you will want to buy one; smaller sizes are cheaper. Also, sooner or later you will want to add a toolchanger/turret; again easier to make for smaller tools.
If you do end up buying Glanze (Chronos in UK), consider getting the screwcutting set at the same time to save shipping. The Glanze set includes two tools that let you use the normally unused edges of the insert, so you get four edges per insert instead of two. Also, have a look at CTC Tools. I believe they sell the holders that take CCMT inserts. I have heard that their shipping is good to Aus.