Apple blossom clematis

A lovely day in the garden today, once the sun came up. I did a breeding bird survey at Cerne Abbas in the morning. It's a matter of walking twice across a 1km square recording all the birds you see or hear - doesn't sound much, but I was surprisingly tired at the end of it. Body clock still not quite right, probably.
Is this a hoverfly or a bee? I think the former.