The sensor is in 3 parts.
The top part in photo is the gear mesh into the gearbox top held in by a bolt through the tab.
The middle part is the actual transducer and screws into the gear mesh assembly
The third , bottom, part is the electric plug. (This is normally the problem, corroded pins giving poor pulse signal to speedometer and EPAS.)
If you have undone the bolt spray , some penetrating fluid around the base , then pull and wiggle should work.
Cheers, and good luck, Mark