They probably are hundreds of pounds each if bought from Land Rover. That is the point people are making to you; go to a dealer or garage and they will use genuine parts and charge you a fortune in labour. Fit them yourself and you not only save on labour costs, but you learn about your vehicle, preventing failures through preventive maintenance, and you can access the wealth of aftermarket and cheaper OEM quality spares that are readily available. Land Rovers are really expensive vehicles to maintain if you let a dealer do it.