Give the brakes a service and new pad setup
Ensure the piston is freely moving and the slider is allowing full movement
Along with a decent bleed to ensure it's not sitting full of crappy fluid

Do the job once
When fitting pads - ensure the can slide smoothly in the carrier, if they cant find out why
Probably corrosion but a good eye and feel should have the braking problem sorted
Next the banging
Have the car on stands, and ensure that the car cant move, but can spin front wheels easily
i'd be then slowing one wheel down to a stop (carefully) and watch the otherside pick up in speed slightly~
Does the knocking suddenly become There?
Repeat for both wheels
If both wheels make the banging, sounds like diff, but whileits banging i'd be checking the moving parts and something will move and next part wont
A pry bar in the joints to ensure the wishbones aren't been playful
And that the engine isn't rocking around as it should
Ziggy