My eye caught this small bee foraging on Oregano (Origanum vulgare). I noticed it due to its peculiar shape and colour, but only after looking at the photo I noticed it was a male Coelioxys bee (Coelioxys sp.). When I tried to photograph him he flew away and went on to forage on Dame’s rocket (Hesperis matronalis).

Possibly it is a male C. elongata since a female of that species was already roaming around the garden for some time.
However the males cannot be distinguished from C. inermis and C. mandibularis without investigating the genitalia.