Has anyone fitted one these ?

Your car already has a cold air intake. Save your money for something useful.

Diesels already have excess cold air from the standard intake, if you're going for a remap just get a good replacement panel filter such as the VW Racing one for £50.  

A CAI will not make any more power - just noise. Even at stage 2. The OEM air box is well designed and provides plenty of cold air. An after market panel filter might get you 1/2hp or may be 1hp. The best mod for your £ is a remap then a better exhaust to flow the gases out properly.