All sensible advice from They Who Know Infinitely More Than I. But… I had exactly the same thing. Got the front o/s sensor replaced, which fixed the speedo etc, but I then got what you seem to be describing, sort of grinding brake pedal – left it in to my local expert, and it was the reluctor ring on the REAR N/S wheel. All sorted now.
Weird or what… either coincidence that both problems should occur more or less simultaneously, or there’s some sort of circuitous alchemy which causes this. A bit like the brake lights coming on ½-strength when a tail light fails
Do a search on threads by me and you'll find it...