Another option is using a grinder cutting wheel. I used a large cutting wheel, but a small cutting wheel like the one in the photo may be strong enough to remove a portion of the fender. A smaller cutting wheel also reduces the risk of damaging other portions of the rack. Fair warning, both the plastic fender and the metal brace underneath are fairly strong so it may take some time, patience and effort to cut thru them. If you haven't used a grinder before, as a rule, always use caution when working with a cutting tool by wearing tinted safety glasses and safety gloves. Always securely attach the wheel making sure it is level, and not canted. Beware the tool can always kick back if not firmly held in place while cutting. When starting
the job, begin slowly and get a feel for the wheel's cutting capability before progressing.