This sounds all very familiar. Are you sure we havent been through this before?

Replacing ECU may not fix your problems. AUS ECU's are matched to the vehicles keys, so to replace your ECU means you will need to change keys. Its complicated.

You said you can't find "someone at a reasonable distance" to diagnose your problems. 1) Who have you been to see thus far about the cars issues, and 2) what is your limit on distance?