As above capital seating sell them on their website. Think they are £46 plus postage. Say £50 in total. Fit perfectly in my CCS. Expensive for what it is but well made.
If your seat is starting to wear I know of a guy in Broxburn Scotland that repairs all Gti seats for main dealers using factory materials seat out and stripped job. His work is better than factory. I did hear that he was working for Lamborghini UK to install embroidery on their cars. He must be good.
PM me if you need his details.