It's in semi shade and although the ground drains well it gets the run off from the shed roof. For the last two years there has also been a vigorous comfrey plant growing behind the bush and in the autumn I have simply left the leaves to rot back into the ground. So too much nitrogen might be a contributing factor. I have two small rosemary plants from cuttings but won't plant them here in case of disease. One I'll put in a pot and the other I'll put at the front of the house where it is sunny and dry.
I've decided to apply my recent permaculture training to help me decide what should be planted in this area in its place. Expect to be bored by sketches, photos and outline plans in the near future!