my rears are KYB, my fronts are Monroe, no reason for different brands, just what i got hold of. Rears about £35 delivered, fronts arounts £60 from a motor factors.
Fronts are a lot more involved. You take the wheel off, then two bolts out the bottom, which on mine were very rusty, i sprayed them every night for a week with WD-40, then gave them a good scrub with a wire brush to get the rust off the thread. Then 3 bolts out the top and the whole unit comes out. Then spring compressors on, you have to get them opposite each other and one as near the top of the spring as possible, the other as near the bottom. (got mine from cromwell tools, £15) Take the tension of the spring, now the hard part, the top nut was an absolute pain! you have to put an allen key in to hold the shocker whilst you turn the nut, my first allen key i turned into something which wouldn't look out of place on a rought iron gate, with the second i managed to split open th end of the shocker. Went to a friend with a pneumatic impact wrench and forced in apart like that. Then the reverse to put it back together. You must use a new top nut, but one should come with the new shocker.
Whilst it's apart check the condition of the bearings and bushes at the top. Once it's back together check for any play on the wheel which shouldn't be there.
Jobs done.
Personally for the fronts i'd call quickfit and get a price, might not be worth all that hassle and buying a set of spring compressors