Lots of Green Hairstreaks after work this afternoon but I again failed to locate any Silver-studded Blues, despite covering Lympstone Common, East Budleigh Common and Bicton Common. The weather was perfect too. I did however manage to find a small colony of Clouded Buffs, close to yesterday's sighting, 5 Dartford Warblers, a few Redpolls and a Nightjar.
A rare glimpse of a Green Hairstreak's upper wing. It's not green!
Large Skipper - this, half a dozen Small Heaths and 3 or 4 Speckled Woods were the only butterfly species noted in warm sunny weather.
Bee species or perhaps a good bee-mimic - not sure - East Budleigh Common.
The 'bee' is actually a hoverfly (note the big eyes!). It's Volucella bombylans and is, as you thought, a bee mimic (for Bombus lacorum - white tailed BB). You can tell the Volucellini (5 sp in the tribe) from three features all of which show up amazingly well on your photo. 1. the 'hairy' aristae 2. the dark patches in the wing and 3. the 're-entrant' outer vein which curves back on itself. There's another common one out at the moment which is V. pellucens - Great pied Hoverfly. See here for one I photoed recently ... https://www.flickr.com/photos/nixexpix/34236642483/