I got the mounting kit from my local Volvo dealership for £18. It's actually a touch more but I asked for discount.
It comprised of a clamp, 2 bolts, copper sealing washer, upper sealing collar and new circlip.
The recommendation is to also fit new high pressure fuel pipes to any injector you remove but I and many haven't bothered and got away with it.
If you want to have a go yourself, it's pretty straightforward with a basic tool kit and my videos are here.
Removal
http://m.youtube.com/watch?v=4aMLT6ZBokk
Installation
http://m.youtube.com/watch?v=bbQhKjj6jis