If you want to stay under the GST threshold ($1000) combined (scope cost plus DHL shipping) then but the TS80 Photoline FPL-53, f7 Doublet. If you can afford the GST and the higher scope cost, of course the TS80, FPL-53, f6 Triplet. The Triplet works out at about $1057 using the DHL shipping option, you can risk it on GST, but if caught its another $106 at least. Keep in mind that both of these scopes use the same focuser (2.5" R&P) which is a very nice, and strong, imaging focuser which can be motorised. You will need a reducer corrector to run either of these scopes at 442 or 379mm respectively at their reduced fl. Both use the same reducer corrector options. I recommend the "3 Photoline Reducer Corrector, its excellent and can be used across the Photoline range if you decide to buy a larger version in the future. The 3" Photoline reducer corrector will cost you 290 euro,, $434 Aud, plus shipping. There are cheaper reducer correctiors, like the 2" version, at $294 Aud, which is ok for APS-C sensors.
Either scope is very nice, and suitable for imaging, and they weigh about the same at 3.1kg and 3.14 respectively.
Btw, i have the TS Flattener and have never used it, as i always run the reducer corrector. Cameras used are: APS"-C and ASI1600.