Link will not open but it should be one kit per caliper.
You might like to do some price comparisons with French suppliers, often more expensive than the UK even with postage taken into account. I have never had to replace the sliders or boots on either of mine, just remove clean and grease. www.Landers-Shop.fr I have found this company very good and on some things the prices are good. www.Pieces-range-rover.com www.Landypoint.fr
Island 4 X 4 are the UK company I use because their carriage costs to France tend to be better than the others.