Refinish Metal Garage Door

I have a single metal garage door whose old paint is flaking badly. Before any colour goes on, the surface needs thorough preparation—scraping away loose paint, and sanding or cleaning until the panel is sound and ready for paint... (Budget: £20 - £250 GBP, Jobs: 3D Modelling, 3D Rendering, Exterior Design, Graphic Design, Painting, Photoshop, Project Planning)