Below shows the difference between 3 types of Mini brake pedal.
They all have the pivot and clevis pin hole fixed to show the differences.
The first pedal is a standard drum brake pedal off a Mk1, the second pedal is a genuine S disc pedal and the third is a late 80's type pedal with the foot pad cut down to earlier size.
The Cooper S disc pedal has the foot pad approx 15mm higher than the drum brake pedal and the later pedal (Mk4 onwards) is another 20mm higher than the S.
More info and discussions on the effect this has on braking feel, etc, when swapping brakes here on Mk1 forum: