In a large pot, over high heat, bring olive oil up to just below smoking point. Add mussels all at once and immediately cover with the lid. Cook for a couple of minutes until shells just start to open, then add wine. Cook until all mussels shells have opened, stirring occasionally to evenly distribute heat. Strain mussels, retaining the stock. Remove mussels from shell, and add back into the stock. Heat through. Ladle 5 mussels and some sauce into bowls. Add the fresh gooseberries, flower petals, and leaves, and serve immediately.