I've used Maplins myself, and I prefer their 'felt' speaker cloth as it's less shiny than the non felt cloth (I have both).
I'me using it to cover my walls and ceiling near the screen (I didn't want any accoustic changes which is why I chose it over normal black felt or vlevet), and it makes quite a visible and measurable difference to the image. Good value too.
I used a local car stereo installer/dealer (loads of colours) in the end to recover a centre speaker that was black and I wanted it silver,
but I did use the company below before. They sent me a sample "book" of all the colours FOC.
Yup, that's the stuff - the felt cloth at the bottom of the three listed. I've mentioned it in the other thread too (seems like I'm repeating myself so I hope that I'm not sounding like a parrot )