Its pretty easy to find this filter inside the rubber tube thing at the bottom of the machine.
Un plug it, take the panel off the back, loosen the metal ring round the black rubber tube and there is the ball filter. i got £1.90, lots of sweetie wrappers, a hair band and some bit of copper wire out of mine.
There was also a load of black stinky sludge.
No wonder the machine smelled bad!! I had already run a couple of super hot washes and put some soda crystals through the machine, but it needed to be physically unblocked. Have a go - its easy!!