Mystery Miner

I found several of these mining bees feeding on dandelion flowers yesterday. I think that brush of hairs on the hind legs, used for collecting pollen and sweeping soil out of the nest tunnels, narrows it down to an Andrena species but I'm not sure which one it is .............any advice?

Wall plants

Inland cliffs are a relatively rare habitat in many parts of Britain but man-made walls are equally acceptable for most cliff-dwelling plants. These two species – ivy-leaved toadflax (aka Kenilworth ivy) and yellow corydalis - are currently in flower on walls around Corbridge in Northumberland. Neither are native – both come from continental Europe – but they’re a welcome addition to our wall flora and put on a good display from spring onwards. Both thrive on walls here and ivy-leaved toadflax has a neat trick of developing fruit stalks with an aversion to light, so that they grow into dark wall crevices and deposit their seed there. The corydalis seed capsules simply burst to scatter their seed, but first the flowers need to be pollinated and today this mining bee seems to have been performing that role – does anyone know what species of bee it is?