I have a L reg 205. It has had a knocking in the steering weel for 7 month. I now have a flat spot on the front tire. swaped for the spare and noticed the pads seem to touch the disc in places.
Fat spots on tyres are usually caused by buckled rims, seriously knackered shocks or wheels that are crazily out of balance - which could easily have caused the steering column knock.
By the second statement, are you saying the pad friction material is worn away?
Non vented discs (Bendix arrangement) are notorious for wearing unevenly.
John