i am still having issues with temp climbing high while crusing on motorway so i want to now install a thermo switch kit to set it to half way so that they come on when i want !
can anyone suggest a place to buy and anything that needs to be done ? i have had a look here but cant find anything related..

If your temp is climbing there is something wrong with your cooling system. Without more info sounds like blown headgasket and or cracked head.

its not pressurising and gas test shows no gases in coolant.. it will idle in the drive for hours and not get hot.. just on runs on the highway at 100-120kph for an hour or it will climb up !
ive done the tests for the relays and all good, as soon as i turn on the boosted air con, both fans cut in full but without , they run as normal but temp comes up too high for my liking ! ...

what switch controls them ? possibly OEM one is out of sync and not turning them on when it should ?

maybe my radiator is shagged ? water camer out rusty looking when i flushed it but when i bought the car, it had been standing for almost a year with only the odd run !

Is not holding pressure because you have a leak somewhere. Thermos are controlled by the ECU and are triggered by a sensor in the thermostat housing.

I FLUSHED IT WITH VINEGAR(good for descaling) AND WATER OVER A 1HR DRIVE/IDLE.. I RECKON ITS A PARTIALLY BLOCKED RAD.. IDLED IN THE DRIVE FOR HALF HOUR came up less than 1/4 guage, NO LEAKS ANYWHERE ! , HOSES WERE FIRM BUT NOT BULGING SO NO HEAD GASKET ISSUE, WATER AFTER THE FLUSH WAS RUSTY RED AND NOT GOOD LOOKING AT ALL SO I WILL REPLACE THE RAD AS I RECKON ITS FLOW WHEN ITS CRUISING ON THE HIGHWAY AND NOT GETTING THE COOLING IT NEEDS...

WELL IF YOU KNOW THE ANSWER WHY ARE YOU ASKING?

i dont know the answer, just accumulating idea's and info as i test/check along the way.. i am not an aussie so not being brought up with these cars, i have limiited knowledge on their quirks and general issues.. been building/importing subaru wrx/sti and gtb's in the UK for last 15 yrs.. they are just too expensive here and also not big enough for my work wagon ! does that help with your question ?

Thermo control is not going to help you with an overheating issue while you are cruising on the motorway mate.

There is already far more flow over the rad at 80-100k's than a thermo generates on its best day......

If the car is idling fine in the driveway and not overheating then there is nothing wrong with the setup of your fans!!

I agree that the problem sounds like a blocked radiator (very similar symptoms to my old EB XR8 that would overheat on the highway when the AC was on). Replaced the rad and all good!!