brackets/ mounts underneath rear

What are the two square brackets under the rear chassis for?  I thought they were for a towbar but all the towbars ive seen just bolt into the bumper bracket holes.
Also there's a bracket next to my petrol tank, has 2 holes in it… any ideas?

Thanks!

Either fuel pump, accumulator or fuel breather

Guess they are for the shell manufacturing process, the 2 rear ones, the one nr the fuel tank could be for the rear brake bias valve.

Aah cheers on the fuel equipment, would make sense.  
Ive got those other brackets on my mk2 polo aswell.  
I'll see if i can find some production line pics, might have a jig or something that they're for.

Found it!