In an earlier contribution to this discussion,

You'll certainly need to bleed the brakes when you've fitted it.

Make a careful note of how that 'orrible bit of springy wire fits on the
outside, so you can put it back in the same way (it's a right sod to get it
to spring into position!). Also note that you'll need a 7mm Allen key (or
male hex socket tool) to undo the pins (behind a rubber/plastic cover) which
hold the calliper in place. 7mm is a non-standard size, and most sets of
Allen keys don't have one!

The whole process is described in more detail in Haynes manual No. 3573.