Bottom arm stess!

Hi people

I need some help badly i am removing bottom arm on mi friends polo 6n(mk4) and the rear bolt that go's throw the bottom arm into subframe then into the car body decided it wanted to snap so i pulled the carpet bk 2 c if i could find a gromit that would reveal the rest of the bolt but all i found was the 1 that covers the chassis leg which the fuel pipes run up bot not remains of a bolt. the only place i could find where it could hide is in part thats below the chassis leg that looks like it was welded onto the chassis leg is this correct or can anyone shed any light on to mi rather large problem plz?

thanks for the help people