Track coastal
"Errrrr...ahem...most TCUs are 30 -40 miles champ."
Well aware of that. The difference is that most TCUs (ie those run by ASA) are also serviced by enroute sectors (also run by ASA) and have the benefit of FLOW control/maestro (also run by ASA). I take my hat off to procedural twr gurus in busy environments, but let's compare granny smiths and golden delicious here - both DN and TL are radar environments.
It often seems to me that inbound acft are "dumped" at the RAAF boundary. If they were subject to FLOW treatment the confliction would have been solved with a minor speed restriction at 80nm instead of a heavy one (or, more likely vectors) inside 40nm.
For example, (at a southern base) we are often handed off an acft at our 40nm boundary and told it has a set course time of XXXXX at 0020 and will probably need some vectors. The XXXXX point is a 40nm IFR reporting/hold point for a capital city airport under ASA control. It is 20nm in from our boundary. So to make it fit we have to give a severe dogleg vector - if the vector were commenced in the enroute sectors airspace the vector could be a much gentler one.
Doesn't bother our military folk much to be flung around the sky, but I think it rather harsh to turn a 737 full of pax 60 degrees for 15nm only to then turn them back again. (I always offer the pilot a holding pattern if they'd prefer and if it's available - but still, pax don't like that whole "oh we're turning around" feeling - I don't when I fly anyway).
I agree that OZ ATC would be a great deal smoother with one ATC provider, however both DN and TL provide outstanding development for RAAF ATCs (and ASA likes us so much more with those ratings in our little blue book!)