It's easy enough for a competent person to DIY. You can wind it back with a screwdriver of similar, but given that you can buy a windback tool for a twenty quid, I would - in fact I did...!! eg
loads on ebay
If you need discs as well, you need a T55 torx bit to extract the caliper bolts.
Jack up and support, remove the wheels
Assuming this doesn't have the big Bosch brakes, then remove the small R clip from the bottom retaining pin, and drive the pin out.
Unhook the handbrake cable, and wiggle it back out through the eye in the caliper (not as easy as it sounds...!)
Unclip the brake pipe from the strut, lift the caliper till it is free of pads (might need a bit of persuasion), the pull it inwards off the top pin. You can now twist the caliper round and rest it on the subframe or somewhere.
Lever the old pads out of the caliper bracket, and give it a good clean
Clean the caliper, and then wind the piston back in - Xantias both go clockwise. You need to push at the same time, which is where the tool makes it much easier.
Fit the new pads to the caliper bracket, with copper slip on the ends, copper slip the backs of the pads where the contact the caliper
Grease the slide pin, and carefully slide the caliper back on, the tilt it down over the pads - make sure that pip on the back of the inner pad drops into the slot in the piston face
Drive the retaining pin back in - making sure that it catches the caliper on the way past and refit the R clip
Reconnect the handbrake cable, and pop the brake pipe back into the strut making sure it is not twisted
Do the other side
Start the engine and apply the brakes a couple of times gently, then give then a couple of good hard pushes, this should adjust up the handbrake.
Drop it back down, and take it for a test run to check all is OK.
If it's got Bosch brakes, then there is a 13mm nut at the bottom rather than the pin, but otherwise it's the same.
If you need to do the discs, then you need to remove the caliper bracket (2 off T55 bolts accessed from the inboard end), then the two small torx screws on the disc face. Knock the disc off the hub, clean the hub face thoroughly, and give them a smear of copperslip before popping the new discs on. If the discs are stubborn you can remove them using the engine - get the disc screws out first, and check the discs will come loose before you remove the pads. If they won't, then start the engine, engage 2nd, and stand on the brakes - this will pull one disc off. Now fit 2 wheel bolts into this hub to hold the disc, and do it again to pull the other side off. Easy!
You may well find that the handbrake cables are broken where the go round the strut - replacement is not that hard.
