Simon,
Pads are a piece of cake to change, no need to remove the caliper.
Undo brake master cylinder cap and leave loose but still in place.
Remove wheels, turn steering to get easier access to caliper. with 1/8 punch knock out the two pins that hold in the pads. Remove cross spring (sprung metal that sits under the pins pushing onto the tops of the pads).
Slide pads up and out of the caliper complete with shims. Push both pistons fully into caliper, I use large pair of swanecks for this, you can also push the pistons in carefully using a prybar between the back of the old pads and the piston before you remove the old pads!. Check master cylinder as you do this to check it doesn't overflow.
Apply copperslip grease to areas where the sides of the new pad touch the caliper, and on the back of the pad and on shims where they contacts the piston.
Slide in new pads with shims, refit cross spring and retaining pins.
Pump brake pedal. Check master cylinder fluid level and adjust if necessary. Refit cap.
Refit wheels.
