Okay. I now have my Pioneer AVIC-X1 installed in my new Altea. I had to get the car audio fitters to use the part I brought from thebassbin.com although they had to trim away at the bottom right of it as it was the infamous LHD version of the fascia trim.
Anyway, everything is in and working well. I am now just waiting for the Seat sat nav fascia trim (part 5p 2 858 071 B 47V) to arrive, once fitted it'll look like a standard trim and it'll be job done.
I will try and post some pics of the unit after installation, along with the Alpine front mounted DVD player and roof mounted screen.