Damson and marrow jam

Yes, I know, it does sound like an unlikely combination but it has turned out to be a match made in heaven!It was a tedious job preparing the damsons, as, despite their external appearance, many had been infiltrated by maggots which was not particularly pleasant! But the healthier fruit and the homegrown marrow have gone together to produce a lush, deep red-coloured jam with the most wonderful plummy flavour that you only get from damsons. So if anybody wants the recipe ......?!