The snake apparently escaped from next door about two weeks ago. I assume it must have made its way into the cavity, and then climbed up to the small hole in the pointing that is level with the door knob. The handle which is a large brass one had been in the sun all morning so must have been nice and warm, which is why I suspect it was wrapped around it.
Now Val is a country girl and is well able to identify adders and grass-snakes, and our garden is full of slow worms, although she still hates them all. However to discover a clearly non indigenous snake, species unknown, venomicity unknown, which moves into an apparent striking position as her hand approached the knob proved just too much of a surprise for rational thought. Actually I suspect I would have been none too delighted either, but I would have killed it on the spot.
G