Hoverfly (Epistrophe grossulariae)
This one needed some real time spent pondering the books at home. In the end those parallel and even spaced black lines on yellow clinched it for me, Epistrophe glossulariae.
I found this one by chance along the path from Ringstead to Osmington as it lapped up the last of the sun before it set beyond Weymouth. Just as the book says, it was along a woodland edge but near umbel flowers.
This is a local species and it was certainly a new find to me. They fly from June to October but July and August when the Hogweed, Wild Carrot and Wild Parsnip are at there best is the most likely time to find them.