remove screws from the inner arch holding the bumper in place, romove inner arch and there is a 10mm (i think) bolt holding the bumper in place just by where the bumper meets the wing, have a feel and you will find it, remove that and take the plastic clips out of the top of the grill. (you may also want to reomve the bolts underneath holding the bumper to the sub frame, i left them in and was fine.)
carefully pull the bumper of on the side that you need to replace. it takes a little bit of force so just ensure that the clips come out and your away.
in all honesty i have probably made it sound harder than it actually is.
hope it helps (sorry i took no pics when i changed mine.)