The grilles are hand made by me from 18mm birch ply specific for these speakers. The acoustic cloth I bought from ebay from this UK seller: https://www.ebay.co.uk/itm/1-4-x-0-5M-S ... 3513936867. It seems only available in one size 1.4m long x 0.5m wide and available in 4 colours. It does look the business and quite easy to apply. I simply used general spray on adhesive applied to the plywood frame.
However, if you want a rainbow of colour options you can buy it from China Ebay seller and it is available in larger sizes: https://www.ebay.co.uk/itm/1-4mx1-0m-Sp ... 0005.m1851.