Found by Rose Stephens on Wanstead Flats, this may be Andrena nigroaenea, the Buffish Mining Bee

The species, according to Falk (2015), may be found in a great variety of habitats and uses a variety of trees and shrubs to forage. It is one of the most common mining bees in the south. It nests on bare ground, so parts of Wanstead Flats - for example in the vicinity of Alexandra Lake - should be a suitable habitat.