White is the only colour without a shade only texture. Just use an emulsion inside but outside use a very good exterior paint, you get what you pay for.
Buy a really tough scrubbing brush for the outside, brush the old paintwork as hard as you can then give a generous coat with a roller, the better quality ext paint the more it will stand the sun and rain. I have done ours once in seven years apart from the original.
Good tip if you do not want to get paint on the tiles, soak the patio with water then lay thin plastic sheet on the tiles, the plastic sticks to it well and will not blow around. Bring some cheap decorators plastic sheets out with you. Don't forget you will need a pole to shove on the roller to get to the high bits.
Not sure about the Chinese paint but there are ironmongers in town that will have good quality paint. I think I paid 50euros for a big tub.
Happy painting.