Cut 4 prunes in half and place them on top of the sausage. Wrap the bacon rasher around both.
Cook in the frying pan, then place in a preheated oven for 5-7 minutes until the bacon is crispy.
Make the mustard mayonnaise by combining the mayonnaise and the mustards, and mixing well together.
Place the sausages in the bowl and finish with grated chestnut and a sprinkling of thyme leaves. Serve alongside the mustard mayonnaise.