I think the bracket is riveted on to the floor (at least they were on my Sporting).
I replaced both with better condition ones from a crashed Panda when I was putting it back together as they were both disintegrating, but I wouldn't have bothered if I didn't have a spare shell to cannibalise.
Tie-wraps will do the same job.
The swing arms have similar brackets. Split a hose that fits over the brake cable and use a couple of zip ties.
I replaced the steel brake pipes from rear axle pivot all the way to the brake. It's about 600mm of braided hose. Cut the old hose and spin the fragment off the underbody steel pipe. You can now clean out the inevitable lifted plastic layer caused by the zinc plating doing its job. Use the hose fragment with the end plugged to stop fluid dripping out. I used P clips and M5 cap heads to hold the new lines but sleeve bobbins and zip ties also work. Brake line makers will add as many grommets/bobbins as you need.