I am in talks with a seller in Portugal who has had a reproduction made of the williams seat material found in the centre of the seats.
On behalf of Williamsclio have asked for a sample prior to placing a club order. He currently sells lots of material for the Renault 5.
prices are expected to be around £80 a meter.
As soon as I receive the sample i will post up my findings. Im not sure how 'deep' the fabric is compared to original.