In reply to TobyA:
> Once you've worked out which ones you need (Decathlon do their own brand ones to fit quite a few different makes and models of brake) actually swapping them is dead easy. A few minutes job.
Um..."should be dead easy". I changed my pads yesterday and could push the pistons back out with minimum hassle, but they would not stay put and within about 10 seconds they had moved back in again. There followed a frustrating hour or so as I tried to work out how the hell I could push the pistons back, insert the new pads, and get the bloody wheel in during the 10 seconds before the pistons moved back out and closed the gap between the new pads. Web searches didn't really clarify enough to make me confident that I knew what I was doing ...in the end I slackened off the "filler cap"(?) on reservoir on the handlebar before very gently and slowly pushing out the pistons back. A few drops of hydraulic fluid came out (which I feverishly and obsessively wiped of the bike, floor, skin etc (as it's supposed to be corrosive or summat?). Lo and behold the pistons behaved and brakes are fine. Could be that new pads were slightly thicker than original ones...?