I've not changed one myself - but the sensor is located behind the exhaust cam sprocket and I believe this requires the sprocket to be removed in order to replace the sensor.Now that my diagnostic kit is all working and the new rad is fitted I gave the engine a run to see what was putting my EML on.
Turns out it's indicating the cam sensor so I wondered if this is a common failure on the Ph1 TS?
Also can it be changed without taking all belts off or can it be done from behind?
Belts are being changed anyway but I thought I'd ask.
Someone else can correct me but I guess you have a choice either of removing the sprocket from the cam (will need a tool to hold the sprocket) or the entire camshaft from the head.
DEFINITELY something to be done while the belts are being changed, though.