Just looked at my invoice from seat,
P/N: 6Q0145834D £25.37
You might want to double check the part number just to make sure it's the right hose. If your local seat are quoting ridiculous amounts then maybe try Ted Johnson on here
The part number or the part?
6Q0145769 CLIP £0.61
6Q0145769A CLIP £0.61
6Q0145834D HOSE £19.96
http://www.seatcupra.net/forums/showthread.php?t=164595&page=2
Think your £100 is for more than you actually need.
My stealer quoted 3 different prices for parts for a cam belt replacement and still got it wrong each time.