I discovered today that there is no need to remove the front bumper if either of the two outside front parking sensors need replacing. I changed my malfunctioning sensor today by simply removing the fog lamp bezel (prises off with your fingers) and removing the 4 torx screws holding in the fog lamp. You then simply pull the whole lamp unit out and it leaves an ideal sized hole for reaching in and accessing the sensor! Job's a good un!  2008 HSE Stornoway Grey with full HST styling.

Nice tip, i have to fit some aftermarket front ones to the wifes so this info could help me out.