I forgot to add to my previous post, that when I went to the local butcher to buy the skin, I asked for it in metres, and after I had been in for the third time, I was being asked to pay more for the same amount and he was considerably grumpy and unwilling.   So I left it for a few months, and then when I went back – I asked him for it by weight, and with a bright cheery voice he said, “no problems – as much as you like”.    So I guess the  moral to this story is, do not ask a non sewing male for sausage skin in metres!