Phew! Just finished my own. This thread was invaluable as reference. I managed it without removing shock, just more awkward and takes longer - mine probably took 5 hours!
The new one is 14mm but same thread. I used a ring spanner and cut a gap out of the ring. I found the best way to screw the new one in was to turn the wire with the sensor (do not pull the wire up into the engine bay until the sensor is screwed in). Once it gets started it easy to finish with ring spanner.
The rubber grommets were difficult to remove but went back in easily with washing up liquid as lubricant.
Good job I went into it as I found a ton of other jobs that need doing now!
Heater flapper boxes are shot, and the Dansk pre-silencer I fitted a few years back (and 02 sensor) are rusted to hell - not good quality at all.
Time for beer....
