Q.Can u tell me what this is please
How to get rid of it if I can or do I have to dig it up and burn it
It looks like your hydrangea has fungal disease, possibly Cercospora leaf spot. Remove heavily affected leaves and pick up any that have dropped. Treat with a fungicide. A rainy spring may be the culprit. When watering, avoid wetting the leaves. Detailed articles on the diseases of hydrangea follows: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/common-hydrangea-diseases.htm http://www.tnstate.edu/extension/documents/Foliar%20diseases%20of%20Hydrangea%20FBG%20022916%20G1.pdf