Green Sawfly

Had a short planning session with another couple of volunteers in the BH this morning and then came home to continue the sanding and painting of our windowsills following the new window installations a couple of weeks ago. 
Lacking in energy, I took a little walk around the garden to look for a blip and came across this very green insect that I thought looked interesting. 
It turns out it's a green sawfly, but as it doesn't look like it's doing any damage and I couldn't see any more, it can stay there.