Hiya Tim
unless your car is a R you don’t have to remove the bumper and the ped sensors can be accessed from the top ,that said if it is an R the sensors can be accessed by removing the front most under tray ,
you will probably find that these sensors are more problematic during the summer season (temperature) however they appear to have a life span of approx 10 years
never knew that you can have a height adjustable spring/standard front strut arrangement other than coil overs are you sure it isn’t the headlights levelling sensor?