canopies and covers are custom made - ask around your/the marina to see which companies work in the area. Often they sew a makers label on the canopies they have made. The F380 cover you have spotted may have been made by Sealine themselves, so probably not available.
I'm in the process of making a similar cover for our flybridge, as the current one only covers half of the area and I spend too much time cleaning it. I quite like the idea of using the grab rails as fixing points, so might incorporate that into my own design... so thanks.