I have now had a chance to quiz brick pointer Johnny about the snake he spotted here at the Welsh Hovel. Johnny said he had never seen a snake in real life before so, after it hissed at him then slithered away, he gave pursuit. Only after work on Saturday did he go on the internet to find out what sort of snake it was.
He met the creature just behind the barns on the edge of what will be the bund ending with a Ha Ha. He says it was fat and at least two foot long. That nails it: it is not an adder but a grass snake, which is not venomous. Having checked the colourings on the internet, Johnny says he also identified it as such. Adders tend to be thinner and only a foot and a half long at most.
So that is all vaguely reassuring though a man who sets off in pursuit of a snake without knowing whether it is an adder or not is a braver man than I am.