I've purchased the colourlock kit, which included brush, de-greaser etc. It's hard work but it's made a world of difference in the car interior.
Before pics:



After brushing, de-greasing and sanding, this is the first layer of the leather dye


Third layer:



Overall, quite pleased with the results! Think I've earned myself a beer or 10.
Before pics:



After brushing, de-greasing and sanding, this is the first layer of the leather dye


Third layer:



Overall, quite pleased with the results! Think I've earned myself a beer or 10.