The two front central parking sensors (nearest to the number plate) are not clicking. Is there a quicker route to them which does not include removing the whole front bumper?
I found the sensor housing to be simple enough to remove from the bumper.
Unclipping the central barrel sensor from the housing was a sod of a job.
As the plastic clips had never moved in years and were easily broken.
It's well worth taking your time and teasing them apart, to allow the sensor to pull/push free.