The stone surround of the front door is painted white and seems to be an overnight hostel for bees, lacewings and other insects but it is a particular favourite of the bees.
Is the attraction warming your bones and wings with the last of the sun before dozing off? By the time morning comes round there are no bees to be seen on the west facing front of the house. They've all moved to the white painted eastern side of the house presumably to catch the morning sun.
Perhaps I'll have to start painting identification numbers on them to see if it is the same bees moving around.
Could this be the beginning of the 159 'Bumble Bee' Squadron?