I ended up buying an APC Smart-X 3000 VA unit (exact model is SMX3000RMHV2U) from ebay for AUD$460. It came with a battery pack dated May 2014 however after running a calibration test today, it's still estimating a runtime of over 1 hour @ 340 watts (240VAC) load, which is still very acceptable. Eventually I'll replace the batteries once they wear out significantly.
Very happy with the purchase. Especially love the ability to configure the unit right from the front panel without resorting to crappy PowerChute software.

I've had several of these units and get more whenever Id like for around $200USD. I flip them on ebay with or without the batteries. I love and swear by them. I built my own DIY 18650 battery bank and the setup menu allows me to create my own charging profile - its priceless for the lab. If you want one, PM me..drawback is they are all wired for US specs.
Heres the link for the auction site I get them:
https://www.bidfta.com/If you buy something and need to to pick it up, PM well before and we can work it out. I go up to Cinci, OH all the time. (live near Nashville, TN). Even the AUssie guys could bid and get one for $200 and Ill ship it over, PM me for details. I ue my Army connections as much as I can for shipping.