Is it possible to repair a car bumper yourself?
Bumper not fender, you are in the UK. Ok I have a Honda Civic with one of these thin bumpers it got quite badly damaged but the plastic could be welded and I filled the remaining dent with body filler. Use a file or sandpaper to smooth to shape, finish with a fine 800 grade wet and dry paper. Prime with a good 3 coats of spray can primer or just 1 coat if you use the proper stuff. Allow to dry for a day and flat (rub down) to a finish with 800 grade wet and dry paper (use water with this to wash away the rubbish from flatting). Remove any wax residue from polish, Mask area and paint to finish.