To prepare the kidney beans, soak 2 cups dried beans in cold water overnight.
In a small jar, combine the raspberry vinegar, honey and wholegrain mustard together. Slowly add the olive oil and stir. Finally add the garlic clove and set the dressing aside to absorb the light garlic flavour.
Drain the water and add to a saucepan with 6 cups fresh water. To improve the digestibility of the bean add a strip of kombu to the water. Bring the water to the boil, before reducing the heat to simmer. Simmer gently for between 50 - 90 minutes until beans are tender. While they are cooking skim off any froth from the pan. Add a pinch of sea salt during the final 10 minutes of cooking. Once cooked remove the kombu and discard. Drain the beans and set aside to cool. Top and tail the green beans and lightly steam for no more than 4 minutes.
Plunge the beans in cold water to stop them cooking further and mix them with the kidney beans.
Remove the garlic clove before mixing it through the beans.