Well, I struggled to get the o2 sensors off, so I ended up taking the cat pipes off. Got one sensor off, fitted anti-fouler, refitted sensor no worries.

Next one, the sensor would not budge - then I noticed the guy who did the welding fitted the pipe & welded close to the sensor weldolet, so he's basically welded the sensor inside the weldolet. Had to break it out and chop it.

So, I need a new sensor and someone to tap the weldolet with a new thread, possibly even a new weldolet and pipe welding on yet, have to see how knackered the thread is.

The saga continues...