I just replaced mine, the instructions were useful. Removing the old footrest was hard after the screw was out - I sat in the driver's seat and pushed / kicked it upwards with my left foot, which pushed it out of its grips and made it easy to release.
The slots on the new one definitely need widening slightly as it was too tight to engage.
I ordered mine from the superskoda site above, it was about £27 with an automatic discount, it arrived in 4 days and is excellent quality.
Thanks!