Quick update here;

The tensioner seems to have gone again, it's rattling when in gear, stopped with your foot on the brake and when the AC is on. I'm guessing the spring

It doesn't show as being out of the wear limit of the spring (via the indicator arrow), but the rattling/vibration it puts through the car is very annoying.

The replacement tensioner has probably only done 10,000 kms

Priced a genuine - $330 apparently.

Might try getting another one from the US this time as others have mentioned in the thread.