knocking noise rear of car

hi, I have a fiat punto 1996, I have just put it through its mot, before i put it through it had a knocking noise from the rear of the car when i turn corners and a louder knocking noise when i go over bumps. to pass mot i had new wheel cylinder. rear brake shoes. got it home and noise was still there took it back and they gave it a road test and said they could'nt see anything loose. and so did nothing the noise when going over bumps seems to be easing off and the knocking noise when i turn corners is getting worse and is knocking as i am just driving. hope you can make sense of all this, it is driving me crazy please help :?: 71000