At the risk of repetition...
I just use deck paint after a good clean and de-grease. When dry run a sander over the surface to take the paint off the raised diamonds.
The treadmaster takes the abuse while the paint is away from abrading feet... and can be cleaned easily. Use a contrasting paint (grey on the buff colour treadmaster looks good).
Obviously there is a limit to a number of times this can be done. I have treated the treadmaster on my cockpit sole three times now. I reckon I can get another treatment before re-covering.
I wouldn't even atttempt to paint Treadmaster with something from B&Q! I have seen painted Treadmaster in the past and it is flaky and the sheen finish of any paint reduces the anti-slip properties of the decking! I have used Treadmaster for many many years and £32 quid for their Treadcote paint, is not much compared to having to replace the decking or remove flaky paint after a bodge job! Good luck! <span style="colorurple"> </span>
I used Treadmaster's own paint, it was very successful. Yes it was expensive, but cheaper than renewing the Treadmaster, and anyway after I sold that boat I advertised the remainder of the paint on the ybw 'for sale' forum and someone snapped it up!