Thanks for that Nic, as a side note what are your opinions of them?
Gavin, It was about £950 including VAT fitting and alignment. Now that everything is on I can only describe the ride as a revalation. It is sooo much smoother. At the moment the car is about 30mm lower than standard and that is about the halfway setting. I'll probably leave it at that for now to see how it copes with all the various speed humps. As for the left rear knocking I've felt since I had the car that was due to the passenger side rear not having a bump stop on and probably as a consequence the shock had started leeking. Not happy as the car was sold as being standard but hey, I guess that's just life. Just glad I changed everything and not just plump for new springs.