Cloddopper - how extremely generous of you to offer me some of your beans

I really appreciate that, but I wouldn't dream of taking them, when you will need them for yourself. Here, it's usually very difficult to get a good crop of runners, and in fact this must be the best year since we moved here 19 years ago. Before that we lived at only about 300' above sea level, so our beans were prolific.
This year I've grown Moonlight, which is an excellent bean, and if picked young is stringless. because my beans are inside a polytunnel, setting can be a bit of a problem, with high temps and fewer insects than outside. We spray the flowers with water, feed, etc, but white flowered varieties work best for us. Last year I lost many whole crops, including my runners, to spider mite - everything wrapped in masses of webs, no crops. We gutted the place last winter, and had the soap spray at the ready this year - that did the trick when the little bu66£rs appeared, and they didn't last long.
So this year I too am saving some of my seed so over the next few years I will develop my own Moonlight version which will suit our particular local conditions.
So although my beans are in theory stringless, I haven't always been able to pick them absolutely on time, when they are small. I don't eat the big fibrous ones, but sometimes beans have got big enough to need stringing. Add to that that my family don't like the least bit of fibre in their beans, and that means I tend to string them all. I probably don't need to, but it's a lifetime's habit I haven't been able to break.