Bee - possibly a chocolate mining bee

Another tiny little bee in the garden.  Despite staring long and hard at the various illustrations in my Collins Complete Guide to British Insects I haven't a Scooby doo what this one is.  (A book that comes complete with a plug from BBC Wildife that it is an excellent resource.)

After some googling on the net, I did wonder whether this might actually be Andrena Scotica - a species which the Collins Complete Guide to British Insects doesn't even mention  ....

I'd quite like it to be Andrena Scotica as it is also known as the chocolate mining bee - and who doesn't want a chocolate mine in their back garden, specially for hungry bees?