recently bought an Ozone IMP 3 line trainer and looking for a place to fly it. I am a total newbie and reason for buying a trainer kite is to eventually progress into kiteboarding lessons.

Don't mind the doctor this happens a lot in the forum world .Beach or park i use my trainer kite. These days i only use it when the wind is crap and i cant use my real kites . Just start using it in 5 to 10 knots and work your way up from there when you start to get the hang of it .

The answer is part of what you need to learn about kiting. Learning about location, and what affect obstructions to the wind have on a kite are very important to know.
Watch this video, a great location is shown, its in Botany Bay, but any open parks, not surrounded by trees - and there are plenty of them across Sydney too, are good locations too.

Watch the video, I do down turns in it. The lines will cross when you down turn but if you fly across the window and downturn on the otherside they will uncross.
Sounds like you just need a bit more practice and in a bit less wind - thats what will make it easier to learn, today was very windy, and not the sort of wind thats easy for learning because the kite pulls too hard and you end up muscling it around instead of feeling what input it needs to do things like downturns. Also a downturn puts the kite into a position where it will fly across the wind window and this will generate maximum power, maybe not such a good idea in strong winds while still learning?