The idea of painting paving seems abad one to me.I think the fact that you cant find a supplier speaks volumes ,but.you can use masonary paint for walls even that has to be re done periodically,personally I would either replace the paving if your unhappy with it or pressure jet it to clean it up.

Is the colour critical? I've used floor paint in the past for a particular project. It's for concrete, is solvent based, and is for light vehicular and foot traffic, so although it's meant for indoor use, it's actually quite tough. However,the colour range aint wide! Green, grey, and a dull red were the only colours I could find! Phil J

Found this on seach - Dulux AquaTread, Dulux Aquatread is a premium quality water based interior/exterior acrylic paving paint that dries to a superior hard wearing satin finish. Its unique Duralink technology provides excellent hot tyre, mar and oil stain resistance and when used over carefully prepared surfaces delivers outstanding adhesion and durability for longer lasting results. Suitable for all concrete paths, driveways, garage floors and patios, inside and out, can even be used to liven up concrete garden pots. Available in satin or as a clear sealer for preserving the natural look of concrete. Dulux True Grip can be added to the paint to assist with slip resistance.