1998 Bravo EFi over heating issue

I am hoping the air con in the ute works before the heat starts lol

You might need to retorque the head if you have anywhere near the mileage I suspect you have on your '98. The bolts get pulled (streached) by the expansion of the head over heat cycles and it creates a seam leak between the block and head. That in turn allows hot combustion gases directly into the water jacket and eventually compromises the cooling system.

I've saved having to do a couple of head gasket jobs that way.

Thanks for the heads up Tweaker Excuse the pun lol
Looks like fishing is out this weekend, will be working on the ute

Call me insane, but for some reason I keep thinking back to water pump.
Took radiator out today, did another flush, nothing concerning came out.
Put radiator back in, bled it, idled it for about an hour to make sure all air had a chance to come out, temp only came up to half. BUT when I turned the motor off, I could hear bubbling behind the new thermostat. Although I knew it opened, temp came up and dropped several times.
I know this isn't normal, I think I am just going insane lol
Oh b u g g e r it, beer time lol

Well that could be a bad water pump, but do.you.hear any whine of sorts? Besides the nagging we normally hear from.you women. LOL just kidding don't sling a boomerwng at me!
But there should be a noticeable whine or squeal from your pump. Tweaker is correct as well, your high heat index mixed with long drives in a desert like area can cause bolts to be untorqued. On that i would replace with new bolts and maybe go ahead an do the head gasket, can save later down the road. Sometimes throwing new parts with old causes premature failure of old parts gaskets etc.

If you decide to retorque the headbolts, make sure to remove the radiator cap first to remove any pressure on the water jacket and also make sure the head is cold.

I'd loosen one bolt then retighten it before moving on to the next bolt.

For your information; you can check for a leaking heads seam by idling the vehicle with the radiator cap off. If you see air bubbles the cylinder gases are being pushed into the water jacket, so what I am suggesting here may save having to put a head gasket on if the bubbling goes away after tightening the headbolts.

I'll get onto that today, thank you

When you opened the drain, you were not only draining the radiator, but the engine too. The suction you heard was air being pulled past the closed thermostat, to replace the draining coolant.

Well, that means there isn't a blockage anywhere So that's a good thing then?
My first thought was that the original "goo" was blocking the cooling system somewhere

It's a good idea to replace the t-stat and cap when you do the radiator, then you can see if there's any goo in there.