Jokari Universal Ladder Tray. Hold Tools, Nails, Screws, Paint, Brushes and Accessories. Hook 3 Bucket Shelf On Any Rung For Auto Storage Platform. Little Attachment Caddy, Giant Benefits (1, Yellow) : Amazon.co.uk:
How do I attach the paint tray to the ladder ? | Hometalk
Tray/shelf ladder attachment for tools & paints. DIY present, made in UK | eBay