Confidence: It's likely to be this, but I can't be certain.
Notes: This hoverfly looks very similar to that identified yesterday as E. latifasciatus - in Nailsea’s Moorend Spout Nature Reserve.
[“Hoverfly on a Bindweed flower” (to iSpot 5th Aug, 2013)].
Again there is an association with water- in today’s case, proximity to a pond which had just re-acquired some water after drying out. So, perhaps this species of hoverfly is at its most visible in wet, or potentially wet areas, whose water has been replenished by recent rain