Either Dasysyrphus or Eupeodes. hairy eyes means the former. I favour that one on the basis of the shape of the abdominal markings, but cannot be certain as I cannot see the eyes clearly enough to see whether they are haired or not.
Many thanks for that Paul. There are only two species listed in my book so now I know of at least two more. Unfortunately the fly did not look up at me - it was too busy feeding! Next time I see one I will try and get an image of its eye. In the meantime I will just mark it down as Scaeva sp.